Stability update with editor & Heroku support

This release fixes some issues with the clipboard that would not place the caret at the right position after pasting code on a composite line.

Also added heroku support so now it's possible to use Ecrire with Heroku. The migration/onboarding on heroku needs a user to get on the application's console and create its first user/password. Even if it's not the end of the world, it would be nice if it would be possible for those credentials to be asked during the migration so it removes an extra step.