add missing migration

migrations/versions/c79c702a1f23_.py

@@ -0,0 +1,33 @@
+"""empty message
+
+Revision ID: c79c702a1f23
+Revises: 4fac8c8a704c
+Create Date: 2019-08-19 21:26:11.924847
+
+"""
+import sqlalchemy_utils
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = 'c79c702a1f23'
+down_revision = '4fac8c8a704c'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column('activation_code', 'expired',
+               existing_type=postgresql.TIMESTAMP(),
+               nullable=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column('activation_code', 'expired',
+               existing_type=postgresql.TIMESTAMP(),
+               nullable=True)
+    # ### end Alembic commands ###