Remove user.provisional column.

This is leftover from a previous iteration of ATAT where inviting a user
to a portfolio would create a pending entry in the users table. This is
no longer used.

alembic/versions/5d7198d34b91_remove_users_provisional.py

@@ -0,0 +1,28 @@
+"""remove users.provisional
+
+Revision ID: 5d7198d34b91
+Revises: 02ac8bdcf16f
+Create Date: 2020-01-09 08:42:34.512191
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '5d7198d34b91' # pragma: allowlist secret
+down_revision = '02ac8bdcf16f' # pragma: allowlist secret
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('users', 'provisional')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('users', sa.Column('provisional', sa.BOOLEAN(), autoincrement=False, nullable=True))
+    # ### end Alembic commands ###