edx/configuration — pull request #864 by carsongee (2014-03-10 19:17:23+00:00)
Title: Added option to specify migration user and changed to admin user and password vars

I'm honestly not 100% sure what is happening in this part of the code, but it seems like we should be able to set the DB user and that we should use the admin password and user vars for migrations instead of the app user. Feel free to correct me though, but I for example don't have a 'root' user in MySQL.