Running

./bin/gmg dbupdate

produces the following backtrace:

​https://gist.github.com/mrvdb/b1f6ed39af8eb5a84944

Git rev: 3f08f780f6698622dba0e8de74ece9194fdb7726

Running gmg dbupdate yields:

sh-4.3$ ./bin/gmg dbupdate
/usr/local/mediagoblin/mediagoblin/mediagoblin/media_types/video/transcoders.py:37: PyGIWarning: GstPbutils was imported without specifying a version first. Use gi.require_version('GstPbutils', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import GstPbutils
/usr/local/mediagoblin/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-i686.egg/sqlalchemy/engine/default.py:471: SAWarning: Unicode type received non-unicode bind param value.
Traceback (most recent call last):
  File "./bin/gmg", line 9, in <module>
    load_entry_point('mediagoblin==0.8.0', 'console_scripts', 'gmg')()
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/__init__.py", line 148, in main_cli
    args.func(args)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/dbupdate.py", line 162, in dbupdate
    run_dbupdate(app_config, global_config)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/dbupdate.py", line 134, in run_dbupdate
    run_alembic_migrations(db, app_config, global_config)
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/gmg_commands/dbupdate.py", line 115, in run_alembic_migrations
    manager = AlembicMigrationManager(Session())
  File "/usr/local/mediagoblin/mediagoblin/mediagoblin/db/migration_tools.py", line 49, in __init__
    self.alembic_cfg.attributes["session"] = self.session
AttributeError: 'Config' object has no attribute 'attributes'

This sounds fairly simple to implement but I might be wrong. If it's just a matter of some SQL-trickery I could give it a try.