Store organisation type against each service

> So that we can default services to their appropriate text allowance,
> we need to find out what sector they're in. So let's start collecting
> that from teams as they create new services.

In order to work out what a team’s allowance should be, we need to know
what part of government they’re from. We’re going to do this logic in
the admin app and then `POST` the allowance to the API.

So all we need to do with the information that the users give us is
store it against the service, so we have a record. Doesn’t need any
logic doing as a result of it, doesn’t need foreign keying to the
organisations table, etc.

migrations/versions/0125_add_organisation_type.py

@@ -0,0 +1,23 @@
+"""
+
+Revision ID: 0125_add_organisation_type
+Revises: 0124_add_free_sms_fragment_limit
+Create Date: 2017-10-05 14:03:00.248005
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = '0125_add_organisation_type'
+down_revision = '0124_add_free_sms_fragment_limit'
+
+
+def upgrade():
+    op.add_column('services', sa.Column('organisation_type', sa.String(length=255), nullable=True))
+    op.add_column('services_history', sa.Column('organisation_type', sa.String(length=255), nullable=True))
+
+
+def downgrade():
+    op.drop_column('services', 'organisation_type')
+    op.drop_column('services_history', 'organisation_type')