change allowed content_type in user avatar

app/models/user.rb

@@ -74,7 +74,7 @@ class User < ApplicationRecord
   after_create :default_role
 
   has_attached_file :avatar, styles: { medium: '300x300>', thumb: '60x60>' }, default_url: ''
-  validates_attachment_content_type :avatar, content_type: %r{ \Aimage\/.*\Z }
+  validates_attachment_content_type :avatar, content_type: ['image/jpg', 'image/jpeg', 'image/png', 'image/gif']
   validates :terms_of_service, acceptance: true
 
   searchkick language: 'brazilian', match: :word_start, searchable: [:name], callbacks: :async