reciprocity/ggrc-core — pull request #917 by danring (2014-01-16 23:09:08+00:00)
Title: Refactor `migrate.py` to use a monkey-patching strategy

* Previously, rewrites of several `alembic.command` functions were
needed; now, all default alembic commands should function correctly
by monkey patching two core functions and extending the argument
parser:
- `EnvironmentContext.__init__` is patched to override `version_table`
argument;
- `ScriptDirectory.from_config` is patched to override the `versions`
directory location to be independent of the location of `env.py`
- `upgradeall` and `downgradeall` are now proper command-line
arguments, and use internal `upgrade` and `downgrade`
implementations