diff --git a/documentation/database/patches/patch-13.sql b/documentation/database/patches/patch-13.sql
new file mode 100644
index 0000000..68721f3
--- /dev/null
+++ b/documentation/database/patches/patch-13.sql
@@ -0,0 +1,2 @@
+ALTER TABLE `{$prefix}user` ADD COLUMN       `user_metawiki` VARCHAR(64);
+ALTER TABLE `{$prefix}user` ADD UNIQUE INDEX `user_metawiki`(`user_metawiki`);
diff --git a/includes/class-QueryUser.php b/includes/class-QueryUser.php
index ef05f49..b2cb9e0 100644
--- a/includes/class-QueryUser.php
+++ b/includes/class-QueryUser.php
@@ -1,67 +1,83 @@
 <?php
 # Linux Day Torino website - classes
 # Copyright (C) 2019 Valerio Bozzolan, Linux Day Torino
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 trait QueryUserTrait {
 
 	/**
 	 * Where the user ID is...
 	 *
 	 * @param int $id
 	 * @return self
 	 */
 	public function whereUserID( $id ) {
 		return $this->whereInt( $this->USER_ID, $id );
 	}
 
 	/**
 	 * Where the user is...
 	 *
 	 * @param  User $user User object
 	 * @return self
 	 */
 	public function whereUser( $user ) {
 		$id = $user->getUserID();
 		return $this->whereUserID( $id );
 	}
 
+	/**
+	 * Where the Meta-wiki username is...
+	 *
+	 * @param string $username Meta-wiki username as displayed after [[User:]] without underscores
+	 * @return self
+	 */
+	public function whereMetaUsername( $username ) {
+		return $this->whereStr( User::META_WIKI, $username );
+	}
+
+	/**
+	 * Join whatever table with the user table
+	 */
+	public function joinUser() {
+		return $this->joinOn( 'INNER', User::T, $this->USER_ID, User::ID_ );
+	}
 }
 
 /**
  * Class useful to retrieve User(s)
  */
 class QueryUser extends Query {
 
 	use QueryUserTrait;
 
 	/**
 	 * Univoque User ID column name
 	 */
 	protected $USER_ID = 'user.user_ID';
 
 	/**
 	 * Constructor
 	 */
 	public function __construct( $db = null ) {
 
 		// choose database and default return class
 		parent::__construct( $db, User::class );
 
 		// choose database table
 		$this->from( User::T );
 	}
 
 }
diff --git a/includes/class-User.php b/includes/class-User.php
index 017719e..eec5580 100644
--- a/includes/class-User.php
+++ b/includes/class-User.php
@@ -1,455 +1,475 @@
 <?php
 # Linux Day 2016 - Construct a database user
 # Copyright (C) 2016, 2017, 2018, 2019 Valerio Bozzolan, Linux Day Torino
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 trait UserTrait {
 
 	/**
 	 * Get the user ID
 	 *
 	 * @return int
 	 */
 	public function getUserID() {
 		return $this->nonnull( User::ID );
 	}
 
 	/**
 	 * Get the user UID
 	 *
 	 * @return string
 	 */
 	public function getUserUID() {
 		return $this->get( User::UID );
 	}
 
 	/**
 	 * Get the user e-mail
 	 *
 	 * @return string
 	 */
 	public function getUserEmail() {
 		return $this->get( User::EMAIL );
 	}
 
 	/**
 	 * Check if the user is public
 	 *
 	 * @return bool
 	 */
 	public function isUserPublic() {
 		return $this->get( User::IS_PUBLIC );
 	}
 
 	/**
 	 * Check if I can see this user
 	 *
 	 * @return bool
 	 */
 	public function isUserVisible() {
 		return $this->isUserPublic() || $this->isUserMyself();
 	}
 
 	/**
 	 * Get the user full name
 	 *
 	 * @return string
 	 */
 	public function getUserFullname() {
 		return sprintf(
 			__("%s %s"),
 			$this->get( User::NAME ),
 			$this->get( User::SURNAME )
 		);
 	}
 
 	/**
 	 * Get the User URL
 	 *
 	 * The User URL is based on the CURRENT_CONFERENCE_UID.
 	 *
 	 * @param boolean $absolute Set to true to force an absolute URL
 	 * @return string
 	 */
 	public function getUserURL( $absolute = false ) {
 		$url = sprintf( PERMALINK_USER,
 			CURRENT_CONFERENCE_UID,
 			$this->getUserUID()
 		);
 		$url = site_page( $url, $absolute );
 		return keep_url_in_language( $url );
 	}
 
 	function getUserLink( $base = null, $html_class = null) {
 		$name = $this->getUserFullname();
 
 		return HTML::a(
 			$this->getUserURL( $base ),
 			esc_html( $name ),
 			sprintf( __("Profilo utente di %s"), $name ),
 			$html_class
 		);
 	}
 
 	/**
 	 * Check if the User has a Gravatar image
 	 *
 	 * @return int
 	 */
 	public function hasUserGravatar() {
 		return $this->has( User::GRAVATAR ) || $this->has( User::EMAIL );
 	}
 
 	/**
 	 * Get the md5 of the E-mail
 	 *
 	 * @return string|null
 	 */
 	public function getUserGravatarUID() {
 		return $this->get( User::GRAVATAR );
 	}
 
 	/**
 	 * Check if the User has an image
 	 *
 	 * @return boolean
 	 */
 	public function hasUserImage() {
 		return $this->has( User::IMAGE ) || $this->has( User::GRAVATAR );
 	}
 
 	/**
 	 * Get the URL of the user image
 	 *
 	 * @param  int     $size     Suggested width
 	 * @param  boolean $absolute Set true to force an absolute URL
 	 * @return string
 	 */
 	public function getUserImage( $size = 256, $absolute = false ) {
 		$image = $this->get( User::IMAGE );
 		if( ! $image ) {
 			$image = 'https://www.gravatar.com/avatar/' . $this->getUserGravatarUID() . '?s=' . $size;
 		}
 		return site_page( $image, $absolute );
 	}
 
 	/**
 	 * It has an user bio?
 	 *
 	 * @return bool
 	 */
 	public function hasUserBio() {
 		return null !== $this->get('user_bio');
 	}
 
 	function getUserBio() {
 		return $this->get('user_bio');
 	}
 
 	function getUserBioHTML($args = []) {
 		return Markdown::parse( __( $this->getUserBIO() ), $args);
 	}
 
 	/**
 	 * Check if the user is somehow social
 	 *
 	 * @return bool
 	 */
 	public function isUserSocial() {
 		foreach( User::allSocialFields() as $field ) {
 			if( $this->has( $field ) ) {
 				return true;
 			}
 		}
 		return false;
 	}
 
 	/**
 	 * Get the user Facebook profile URL
 	 *
 	 * @return string URL
 	 */
 	public function getUserFacebruck() {
 		return 'https://facebook.com/' . $this->get( User::FACEBOOK );
 	}
 
 	/**
 	 * Get the user Google+ profile URL
 	 *
 	 * @return string URL
 	 */
 	public function getUserGuggolpluz() {
 		return 'https://plus.google.com/' . $this->get( User::GOOGLE_PLUS );
 	}
 
 	/**
 	 * Get the user Twitter profile URL
 	 *
 	 * @return string URL
 	 */
 	public function getUserTuitt() {
 		return 'https://twitter.com/' . $this->get( User::TWITTER );
 	}
 
 	/**
 	 * Get the user Linkedin profile URL
 	 *
 	 * @return string URL
 	 */
 	public function getUserLinkeddon() {
 		return 'https://www.linkedin.com/in/' . $this->get( User::LINKEDIN );
 	}
 
 	/**
 	 * Get the user GitHub profile URL
 	 *
 	 * @return string URL
 	 */
 	public function getUserGithubbo() {
 		return 'https://github.com/' . $this->get( User::GITHUB );
 	}
 
+	/**
+	 * Get the user Wikimedia Meta-wiki URL
+	 *
+	 * @return string
+	 */
+	public function getUserMetaWikiURL() {
+		$username = $this->get( User::META_WIKI );
+		$username = str_replace( ' ', '_', $username );
+		return sprintf(
+			'https://meta.wikimedia.org/wiki/User:%s',
+			$username
+		);
+	}
+
 	/**
 	 * Get the edit URL to this user
 	 *
 	 * @return string
 	 */
 	public function getUserEditURL() {
 		$url = http_build_get_query( '2016/user-edit.php', [
 			'uid' => $this->getUserUID(),
 		] );
 		return site_page( $url );
 	}
 
 	/**
 	 * Can you edit this user?
 	 *
 	 * @return bool
 	 */
 	public function hasPermissionToEditUser() {
 		if( has_permission('edit-users') ) {
 			return true;
 		}
 		if( has_permission('edit-account') && $this->isUserMyself() ) {
 			return true;
 		}
 		return false;
 	}
 
 	/**
 	 * Is this user myself?
 	 *
 	 * @return bool
 	 */
 	public function isUserMyself() {
 		return is_logged() && get_user()->getUserID() === $this->getUserID();
 	}
 
 	/**
 	 * Check if the User has a loved license
 	 *
 	 * @return
 	 */
 	public function hasUserLovelicense() {
 		return $this->has( User::LOVED_LICENSE );
 	}
 
 	/**
 	 * Get the User loved license
 	 *
 	 * @return License
 	 */
 	public function getUserLovelicense() {
 		return license( $this->get( User::LOVED_LICENSE ) );
 	}
 
 	function factoryUserSkills() {
 		return UserSkill::factorySkillByUser( $this->getUserID() );
 	}
 
 	function factoryUserEvents() {
 		return FullEvent::factoryByUser( $this->getUserID() );
 	}
 
 	/**
 	 * Normalize a User object
 	 */
 	protected function normalizeUser() {
 		$this->integers( User::ID );
 		$this->booleans(
 			User::IS_PUBLIC,
 			User::IS_ACTIVE
 		);
 	}
 }
 
 class User extends Sessionuser {
 	use UserTrait;
 
 	/**
 	 * Name column
 	 */
 	const NAME = 'user_name';
 
 	/**
 	 * Aristocratic title column
 	 */
 	const ARISTOCRATIC_TITLE = 'user_title';
 
 	/**
 	 * ID column
 	 */
 	const SURNAME = 'user_surname';
 
 	/**
 	 * He/she public column
 	 */
 	const IS_PUBLIC = 'user_public';
 
 	/**
 	 * Image column
 	 */
 	const IMAGE = 'user_image';
 
 	/**
 	 * E-mail
 	 */
 	const EMAIL = 'user_email';
 
 	/**
 	 * Gravatar column
 	 */
 	const GRAVATAR = 'user_gravatar';
 
 	/**
 	 * RSS column
 	 */
 	const RSS = 'user_rss';
 
 	/**
 	 * Facebook username column
 	 */
 	const FACEBOOK = 'user_fb';
 
 	/**
 	 * Linkedin username column
 	 */
 	const LINKEDIN = 'user_lnkd';
 
 	/**
 	 * Google+ username column
 	 */
 	const GOOGLE_PLUS = 'user_googl';
 
 	/**
 	 * Twitter username
 	 */
 	const TWITTER = 'user_twtr';
 
 	/**
 	 * GitHub username
 	 */
 	const GITHUB = 'user_github';
 
 	/**
 	 * Personal website column
 	 */
 	const WEBSITE = 'user_site';
 
 	/**
 	 * Loved license column
 	 */
 	const LOVED_LICENSE = 'user_lovelicense';
 
 	/**
 	 * Biography column
 	 */
 	const BIO = 'user_bio';
 
+	/**
+	 * Username in Meta-wiki
+	 */
+	const META_WIKI = 'user_metawiki';
+
 	/**
 	 * Complete ID column name
 	 */
 	const ID_ = self::T . DOT . self::ID;
 
 	/**
 	 * Maximum UID length
 	 */
 	const MAXLEN_UID = 64;
 
 	/**
 	 * Constructor
 	 */
 	public function __construct() {
 		$this->normalizeUser();
 	}
 
 	/**
 	 * Get all the user social fields
 	 *
 	 * @return array
 	 */
 	public static function allSocialFields() {
 		return [
 			User::RSS,
 			User::FACEBOOK,
 			User::LINKEDIN,
 			User::GOOGLE_PLUS,
 			User::TWITTER,
 			User::GITHUB,
+			User::META_WIKI,
 		];
 	}
 
 	/**
 	 * Factory users by an event
 	 *
 	 * @param $event_ID int
 	 * @return Query
 	 */
 	public static function factoryByEvent( $event_ID ) {
 		return self::factory()
 			->from('event_user')
 			->equals('event_user.user_ID', 'user.user_ID')
 			->whereInt('event_user.event_ID', $event_ID );
 	}
 
 	/**
 	 * Generate the appropriate SELECT for the User Bio
 	 *
 	 * @return string
 	 */
 	public static function BIO_L10N() {
 		return i18n_coalesce( 'user_bio', 'user_bio_%s' );
 	}
 
 	/**
 	 * Get all the public User fields
 	 *
 	 * @return array
 	 */
 	public static function fields() {
 		return [
 			self::ID,
 			self::UID,
 			self::GRAVATAR,
 			self::NAME,
 			self::SURNAME,
 			self::IMAGE,
 			self::WEBSITE,
 			self::LOVED_LICENSE,
 			self::BIO_L10N(),
 		];
 	}
 
 }