Add more column ignores

app/models/issue.rb

@@ -14,6 +14,7 @@ class Issue < ApplicationRecord
   include TimeTrackable
   include ThrottledTouch
   include LabelEventable
+  include IgnorableColumns
 
   DueDateStruct                   = Struct.new(:title, :name).freeze
   NoDueDate                       = DueDateStruct.new('No Due Date', '0').freeze
@@ -68,8 +69,7 @@ class Issue < ApplicationRecord
 
   scope :counts_by_state, -> { reorder(nil).group(:state_id).count }
 
-  # Only remove after 2019-12-22 and with %12.7
-  self.ignored_columns += %i[state]
+  ignore_column :state, remove_with: '12.7', remove_after: '2019-12-22'
 
   after_commit :expire_etag_cache
   after_save :ensure_metrics, unless: :imported?

app/models/merge_request.rb

@@ -17,6 +17,7 @@ class MergeRequest < ApplicationRecord
   include FromUnion
   include DeprecatedAssignee
   include ShaAttribute
+  include IgnorableColumns
 
   sha_attribute :squash_commit_sha
 
@@ -231,8 +232,7 @@ class MergeRequest < ApplicationRecord
     with_state(:opened).where(auto_merge_enabled: true)
   end
 
-  # Only remove after 2019-12-22 and with %12.7
-  self.ignored_columns += %i[state]
+  ignore_column :state, remove_with: '12.7', remove_after: '2019-12-22'
 
   after_save :keep_around_commit
 

app/models/project_ci_cd_setting.rb

 # frozen_string_literal: true
 
 class ProjectCiCdSetting < ApplicationRecord
-  # TODO: remove once GitLab 12.7 is released
+  include IgnorableColumns
   # https://gitlab.com/gitlab-org/gitlab/issues/36651
-  self.ignored_columns += %i[merge_trains_enabled]
+  ignore_column :merge_trains_enabled, remove_with: '12.7', remove_after: '2019-12-22'
+
   belongs_to :project, inverse_of: :ci_cd_settings
 
   # The version of the schema that first introduced this model/table.