capistrano/rails — pull request #86 by mtparet (2014-09-22 20:37:21+00:00)
Title: Bring back custom migrate environment variable

With Capistrano 2.X it was possible to define custom
environment variables for the migration. This commit
brings back this feature.
https://github.com/capistrano/capistrano/blob/legacy-v2/lib/capistrano/recipes/deploy.rb#L438