Only allow one session

alembic/versions/ab1167fc8260_add_user_last_session_id.py

@@ -0,0 +1,28 @@
+"""add_user_last_session_id
+
+Revision ID: ab1167fc8260
+Revises: 432c5287256d
+Create Date: 2019-05-15 16:25:48.766451
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = 'ab1167fc8260'
+down_revision = '432c5287256d'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('users', sa.Column('last_session_id', postgresql.UUID(as_uuid=True), server_default=sa.text('uuid_generate_v4()'), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('users', 'last_session_id')
+    # ### end Alembic commands ###