Feature request: Allow ability to add git repo to travis

[ml27299]

Hi, thx for your work so far on this project. I was wondering if you could add the ability to a subscribe a git repo to travis via this terraform provider. The end-point for this takes more than one step to achieve this:

Force a synchronization just to make sure the repo will be there
Use users/sync end-point

Obtain the repository ID (yes, you must have it)
Use repos/repo.slug end-point

Flick the switch
Use hooks/repo.id end-point