Update model

- adds email_from field to the service model
- adds subject_line to the template model

These are unique and not null fields, so there is a migration here for email_from to populate it.

migrations/versions/0017_emailfrom_notnull.py

@@ -0,0 +1,26 @@
+"""empty message
+
+Revision ID: 0017_emailfrom_notnull
+Revises: 0016_add_email_from
+Create Date: 2016-02-18 11:41:25.753694
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '0017_emailfrom_notnull'
+down_revision = '0016_add_email_from'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.alter_column('services', 'email_from',
+                    existing_type=sa.TEXT(),
+                    nullable=False)
+
+
+def downgrade():
+    op.alter_column('services', 'email_from',
+                    existing_type=sa.TEXT(),
+                    nullable=True)