Add Alembic support from alchemy cookiecutter#3307

Merged

mmerickel merged 26 commits intomasterfrom alembic-cookiecutter-alchemy

Aug 5, 2018

+1,676-622

Commits on Jun 23, 2018

Update source files for installation step with new alembic support
stevepiercy
committed
Update source files for basiclayout step for Alembic support
stevepiercy
committed
Add mention of migrations and Alembic in design and glossary.
stevepiercy
committed

Commits on Jun 25, 2018

Commits on Jun 27, 2018

switch to engine_from_config to be consistent with run_migrations_offline
stevepiercy
committed
Add alembic directory to source in models step
stevepiercy
committed