Adds draft column to merge_requests table

changelogs/unreleased/330274-add-a-boolean-column-for-tracking-mr-draft-status.yml

+---
+title: Add draft column to merge_requests table
+merge_request: 61681
+author:
+type: other

db/migrate/20210513093418_add_draft_column_to_merge_requests.rb

+# frozen_string_literal: true
+
+class AddDraftColumnToMergeRequests < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  # When using the methods "add_concurrent_index" or "remove_concurrent_index"
+  # you must disable the use of transactions
+  # as these methods can not run in an existing transaction.
+  # When using "add_concurrent_index" or "remove_concurrent_index" methods make sure
+  # that either of them is the _only_ method called in the migration,
+  # any other changes should go in a separate migration.
+  # This ensures that upon failure _only_ the index creation or removing fails
+  # and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def up
+    with_lock_retries do
+      add_column :merge_requests, :draft, :boolean, default: false, null: false
+    end
+  end
+
+  def down
+    with_lock_retries do
+      remove_column :merge_requests, :draft
+    end
+  end
+end

db/schema_migrations/20210513093418

+f2c85121d217aa953b6ae52e32624cf4164b1f1408bcbe8ae3facafc15b037ce
\ No newline at end of file

db/structure.sql

@@ -14703,6 +14703,7 @@ CREATE TABLE merge_requests (
     squash_commit_sha bytea,
     sprint_id bigint,
     merge_ref_sha bytea,
+    draft boolean DEFAULT false NOT NULL,
     CONSTRAINT check_970d272570 CHECK ((lock_version IS NOT NULL))
 );