Change repo to repo.rb, update reset-squash-r3.png

[dunxen]

Change repo to repo.rb for commit messages to correspond.

Closes#231.

[dunxen]

This should also complete PR #231.
If you would like me to also export diagram source as SVG I can do that too.

[ben]

If you would like me to also export diagram source as SVG I can do that too.

That would be awesome, actually. Sketch worked well for us when developing the diagrams, but maintaining them is a job better left to SVG. That's a separate PR, however.

For this one, I just see one issue: the exported image size. Since we're not printing these, we're trying to keep the e-book versions a manageable file size, so can you shrink to the old dimensions and run pngcrush?

[dunxen]

Hey!

Yeah I’ll do that as soon as I get to the office in the morning (accidentally left my laptop there). Then I'll rebase and push. Sorry about that!

I’ll do a separate PR for the SVG source after that!

[ben]

Sorry for the delay, thanks!