Use self.ignored_columns += instead of =

This is to accomodate prepended modules.

app/models/application_setting.rb

@@ -32,13 +32,13 @@ class ApplicationSetting < ApplicationRecord
   serialize :asset_proxy_whitelist, Array # rubocop:disable Cop/ActiveRecordSerialize
 
   self.ignored_columns += %i[
-                         clientside_sentry_dsn
-                         clientside_sentry_enabled
-                         koding_enabled
-                         koding_url
-                         sentry_dsn
-                         sentry_enabled
-                         ]
+    clientside_sentry_dsn
+    clientside_sentry_enabled
+    koding_enabled
+    koding_url
+    sentry_dsn
+    sentry_enabled
+  ]
 
   cache_markdown_field :sign_in_text
   cache_markdown_field :help_page_text

app/models/ci/build.rb

@@ -18,13 +18,13 @@ module Ci
     BuildArchivedError = Class.new(StandardError)
 
     self.ignored_columns += %i[
-                           artifacts_file
-                           artifacts_file_store
-                           artifacts_metadata
-                           artifacts_metadata_store
-                           artifacts_size
-                           commands
-                           ]
+      artifacts_file
+      artifacts_file_store
+      artifacts_metadata
+      artifacts_metadata_store
+      artifacts_size
+      commands
+    ]
 
     belongs_to :project, inverse_of: :builds
     belongs_to :runner

app/models/user.rb

@@ -24,10 +24,10 @@ class User < ApplicationRecord
   DEFAULT_NOTIFICATION_LEVEL = :participating
 
   self.ignored_columns += %i[
-                         authentication_token
-                         email_provider
-                         external_email
-                         ]
+    authentication_token
+    email_provider
+    external_email
+  ]
 
   add_authentication_token_field :incoming_email_token, token_generator: -> { SecureRandom.hex.to_i(16).to_s(36) }
   add_authentication_token_field :feed_token