Use FIXME instead, feedback from:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4093/diffs#note_12501400

app/models/ci/runner.rb

@@ -27,7 +27,7 @@ module Ci
     end
 
     scope :available_for, ->(project) do
-      # TODO: That `to_sql` is needed to workaround a weird Rails bug.
+      # FIXME: That `to_sql` is needed to workaround a weird Rails bug.
       #        Without that, placeholders would miss one and couldn't match.
       where(locked: false).
         where.not("id IN (#{project.runners.select(:id).to_sql})").specific