support: allow users to attach a service to their tickets

Tickets now have a dropdown box to select a service for their tickets (or they can leave the box alone to go with no service).

![dropdown](http://i.imgur.com/ZmgHYca.png)

Ticket lists will display VPS nicknames.

![ticket list](http://i.imgur.com/UFhKt9g.png)

As will the ticket, for both the admins and the user.

![ticket](http://i.imgur.com/Ibryzkh.png)

We're going to need to add a service to the ticket table, like so:

```sql
ALTER TABLE ticket ADD service_id INTEGER;
ALTER TABLE ticket ADD FOREIGN KEY(service_id) REFERENCES services (id);
```