migrations updates:

- retain relevant task order data when migrating request bodies
- set revision relationship for status events
- make relationship between status events and revisions not nullable

alembic/versions/e66a49285f23_add_relationship_between_revision_and_.py

@@ -7,20 +7,32 @@ Create Date: 2018-09-04 14:01:31.548665
 """
 from alembic import op
 import sqlalchemy as sa
+from sqlalchemy.orm import sessionmaker
 from sqlalchemy.dialects import postgresql
 
+from atst.models.request import Request
+
 # revision identifiers, used by Alembic.
 revision = 'e66a49285f23'
 down_revision = '090e1bd0d7ce'
 branch_labels = None
 depends_on = None
 
+from uuid import UUID
+
 
 def upgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.add_column('request_status_events', sa.Column('request_revision_id', postgresql.UUID(as_uuid=True), nullable=False))
+    op.add_column('request_status_events', sa.Column('request_revision_id', postgresql.UUID(as_uuid=True)))
     op.create_foreign_key(None, 'request_status_events', 'request_revisions', ['request_revision_id'], ['id'])
-    # ### end Alembic commands ###
+
+    Session = sessionmaker(bind=op.get_bind())
+    session = Session()
+    for request in session.query(Request).all():
+        for status in request.status_events:
+            status.revision = request.latest_revision
+            session.add(status)
+
+    session.commit()
 
 
 def downgrade():