Inject the tables metadata into the upgrade and downgrade functions. Fix a bunch of the downgrades to actually work.

data/migrations/versions/f42b0ea7a4d_remove_the_old_webhooks_table.py

@@ -14,13 +14,13 @@ from alembic import op
 import sqlalchemy as sa
 from sqlalchemy.dialects import mysql
 
-def upgrade():
+def upgrade(tables):
     ### commands auto generated by Alembic - please adjust! ###
     op.drop_table('webhook')
     ### end Alembic commands ###
 
 
-def downgrade():
+def downgrade(tables):
     ### commands auto generated by Alembic - please adjust! ###
     op.create_table('webhook',
     sa.Column('id', mysql.INTEGER(display_width=11), nullable=False),