Collaborating / Pull Requests

[JimCircadian]

I think there should be some instructor notes for pull requests rather than collaborating, which appears to be a broken link.

It would be useful if we have instruction for the instructor on setting up the master repository (countries in the example) so that they can demonstrate things during the lesson.

We're giving this workshop tomorrow, so expect a PR to try and (start) resolv(ing) this! 😄

### Tasks
- [ ] Update instructor notes
- [ ] Include details on setting up repository for "pull requests" lesson
- [ ] Make sure consistent across learner and instructor materials

[sstevens2]

great idea! maybe we should move this to the workbench too so we can then use the inline instructor notes feature. That would be especially helpful in that section.