diff --git a/app/models/group.rb b/app/models/group.rb
index a17f5c3..8b8fa4e 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -1,5 +1,6 @@
 class Group < ApplicationRecord
   has_many :asds
   has_many :special_events
   validates :chat_id, uniqueness: true
+  validates :chat_id, :numericality => {:less_than_or_equal_to => 0 }
 end
diff --git a/app/models/sender.rb b/app/models/sender.rb
index ad86ebd..aa00841 100644
--- a/app/models/sender.rb
+++ b/app/models/sender.rb
@@ -1,4 +1,5 @@
 class Sender < ApplicationRecord
   has_many :asds
   validates :chat_id, uniqueness: true
+  validates :chat_id, :numericality => { :greater_than_or_equal_to => 0 }
 end