fix mistake in 0.17 upgrade: task status should be non-NULLable

Change-Id: I286e4a2625b95d0e7cb4c49018cff48ac3ef9e2d
avoid duplicate indexes on lab_controller.user_id

Change-Id: I4302bc6efede6001f9b98f6e1271577dd6f4a43e
index tg_user.email_address

The 0.17 schema upgrade notes (unintentionally) added this index, but
it's useful to have so we might as we add it properly.

Change-Id: Ib4c946724a46b909e3f83658de9fa7f63ac61bec
port pending SQL upgrades to Alembic

Change-Id: I8527f309a467fa9e8be75f77a43ea64ae23334de
test automated schema migrations

Bug: 682030
Change-Id: Ic70cbcc2f63d99db011f43bd999163331582ccbb
back-populated db migrations back to 0.12

Bug: 682030
Change-Id: I6667b2444f684af2a1fc06f2e8ac0c3d75e6aa01
fix mistake in 0.15 upgrade: group_name should be non-NULLable

Change-Id: Ibda887cb4717141087fba2ba99b662f34e3329f0
fix mistake in 0.13 upgrade: is_owner should be non-NULLable

Change-Id: I96667cf7066b1537706a89fab06448f108bae4d5
automatically determine existing schema version when upgrading

Bug: 682030
Change-Id: I37594b0fcd451245270ad36b8769fb76fac242ef