Add `datetime_with_timezone` to table definition

So the method can be used in a `create_table` block. There is a new Rubocop style cop that requires the usage of `datetime_with_timezone`.

config/initializers/active_record_table_definition.rb

@@ -3,15 +3,15 @@
 
 require 'active_record/connection_adapters/abstract/schema_definitions'
 
-# Appends columns `created_at` and `updated_at` to a table.
-#
-# It is used in table creation like:
-# create_table 'users' do |t|
-#   t.timestamps_with_timezone
-# end
 module ActiveRecord
   module ConnectionAdapters
     class TableDefinition
+      # Appends columns `created_at` and `updated_at` to a table.
+      #
+      # It is used in table creation like:
+      # create_table 'users' do |t|
+      #   t.timestamps_with_timezone
+      # end
       def timestamps_with_timezone(**options)
         options[:null] = false if options[:null].nil?
 
@@ -19,6 +19,16 @@ module ActiveRecord
           column(column_name, :datetime_with_timezone, options)
         end
       end
+
+      # Adds specified column with appropriate timestamp type
+      #
+      # It is used in table creation like:
+      # create_table 'users' do |t|
+      #   t.datetime_with_timezone :did_something_at
+      # end
+      def datetime_with_timezone(column_name, **options)
+        column(column_name, :datetime_with_timezone, options)
+      end
     end
   end
 end