Implement final review comments from @rymai.

1. Instantiate `ProtectedBranchesAccessSelect` from `dispatcher`

2. Use `can?(user, ...)` instead of `user.can?(...)`

3. Add `DOWNTIME` notes to all migrations added in !5081.

4. Add an explicit `down` method for migrations removing the
   `developers_can_push` and `developers_can_merge` columns, ensuring that
   the columns created (on rollback) have the appropriate defaults.

5. Remove duplicate CHANGELOG entries.

6. Blank lines after guard clauses.

1 files changed, 12 insertions, 1 deletions

diff --git a/db/migrate/20160705055809_remove_developers_can_push_from_protected_branches.rb b/db/migrate/20160705055809_remove_developers_can_push_from_protected_branches.rb
index ad6ad43686d..f563f660ddf 100644
--- a/db/migrate/20160705055809_remove_developers_can_push_from_protected_branches.rb
+++ b/db/migrate/20160705055809_remove_developers_can_push_from_protected_branches.rb
@@ -2,7 +2,18 @@
 # for more information on how to write migrations for GitLab.
 
 class RemoveDevelopersCanPushFromProtectedBranches < ActiveRecord::Migration
-  def change
+  include Gitlab::Database::MigrationHelpers
+
+  # This is only required for `#down`
+  disable_ddl_transaction!
+
+  DOWNTIME = false
+
+  def up
     remove_column :protected_branches, :developers_can_push, :boolean
   end
+
+  def down
+    add_column_with_default(:protected_branches, :developers_can_push, :boolean, default: false, null: false)
+  end
 end