add gen_email.custom_domain_id foreign key

app/models.py

@@ -402,6 +402,10 @@ class GenEmail(db.Model, ModelMixin):
     # this email has been customized by user, i.e. not generated randomly
     custom = db.Column(db.Boolean(), default=False, nullable=False, server_default="0")
 
+    custom_domain_id = db.Column(
+        db.ForeignKey("custom_domain.id", ondelete="cascade"), nullable=True
+    )
+
     user = db.relationship(User)
 
     @classmethod

migrations/versions/5e868298fee7_.py

@@ -0,0 +1,31 @@
+"""empty message
+
+Revision ID: 5e868298fee7
+Revises: 0b28518684ae
+Create Date: 2019-12-02 00:28:40.281432
+
+"""
+import sqlalchemy_utils
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '5e868298fee7'
+down_revision = '0b28518684ae'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('gen_email', sa.Column('custom_domain_id', sa.Integer(), nullable=True))
+    op.create_foreign_key(None, 'gen_email', 'custom_domain', ['custom_domain_id'], ['id'], ondelete='cascade')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(None, 'gen_email', type_='foreignkey')
+    op.drop_column('gen_email', 'custom_domain_id')
+    # ### end Alembic commands ###