Also store consent to research against a service

It makes most sense to collect this at the same time as the estimated
volumes. Which means we need to store it somewhere; we can’t put it
straight into the ticket.

app/models.py

@@ -364,6 +364,7 @@ class Service(db.Model, Versioned):
     volume_sms = db.Column(db.Integer(), nullable=True, unique=False)
     volume_email = db.Column(db.Integer(), nullable=True, unique=False)
     volume_letter = db.Column(db.Integer(), nullable=True, unique=False)
+    consent_to_research = db.Column(db.Boolean, nullable=False, default=False)
 
     organisation = db.relationship(
         'Organisation',