I struggled a bit when trying to install this bundle yesterday... I think both pages of the documentation are wrong. This pull request fixes this page http://symfony.com/doc/current/bundles/DoctrineMigrationsBundle/index.html .
Regarding this page : http://symfony.com/doc/master/bundles/DoctrineMigrationsBundle/index.html , I think something misses in autoload.php, and I tried specifying an array of folders to make the Doctrine namespace correspond to both the bundle and the doctrine library. I didn't get it to work though, so no pull request for this one...
This is branch 2.0, so telling people to use it makes sense, doesn'it?