Singular ignore_column method

app/models/ci/runner.rb

@@ -36,7 +36,7 @@ module Ci
 
     FORM_EDITABLE = %i[description tag_list active run_untagged locked access_level maximum_timeout_human_readable].freeze
 
-    ignore_columns :is_shared, remove_after: '2019-12-15', remove_with: '12.6'
+    ignore_column :is_shared, remove_after: '2019-12-15', remove_with: '12.6'
 
     has_many :builds
     has_many :runner_projects, inverse_of: :runner, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent

app/models/concerns/ignorable_columns.rb

@@ -12,5 +12,7 @@ module IgnorableColumns
 
       self.ignored_columns += columns
     end
+
+    alias_method :ignore_column, :ignore_columns
   end
 end

app/models/deploy_key.rb

@@ -11,7 +11,7 @@ class DeployKey < Key
   scope :are_public,  -> { where(public: true) }
   scope :with_projects, -> { includes(deploy_keys_projects: { project: [:route, :namespace] }) }
 
-  ignore_columns :can_push, remove_after: '2019-12-15', remove_with: '12.6'
+  ignore_column :can_push, remove_after: '2019-12-15', remove_with: '12.6'
 
   accepts_nested_attributes_for :deploy_keys_projects
 

app/models/project.rb

@@ -65,7 +65,7 @@ class Project < ApplicationRecord
 
   # TODO: remove once GitLab 12.5 is released
   # https://gitlab.com/gitlab-org/gitlab/issues/34638
-  ignore_columns :merge_requests_require_code_owner_approval, remove_after: '2019-12-01', remove_with: '12.6'
+  ignore_column :merge_requests_require_code_owner_approval, remove_after: '2019-12-01', remove_with: '12.6'
 
   default_value_for :archived, false
   default_value_for :resolve_outdated_diff_discussions, false

ee/app/models/operations/feature_flags_client.rb

@@ -6,7 +6,7 @@ module Operations
     include IgnorableColumns
 
     self.table_name = 'operations_feature_flags_clients'
-    ignore_columns :token, remove_after: '2019-12-15', remove_with: '12.6'
+    ignore_column :token, remove_after: '2019-12-15', remove_with: '12.6'
 
     belongs_to :project