Validate email addresses using Devise.email_regexp

Also:
- Get rid of legacy :strict_mode
- Get rid of custom :email validator
- Add some shared examples to spec emails validation

1 files changed, 2 insertions, 2 deletions

diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index fa48fe5b9e4..ac6653f5d50 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -71,8 +71,8 @@ class ApplicationSetting < ActiveRecord::Base
             url: true
 
   validates :admin_notification_email,
-            allow_blank: true,
-            email: true
+            format: { with: Devise.email_regexp },
+            allow_blank: true
 
   validates :two_factor_grace_period,
             numericality: { greater_than_or_equal_to: 0 }