Update readme

[professor]

• This makes it clear that this repo is for both bookbinder and bookbindery. Before, it sounded like bookbinder was a separate repo

[cfdreddbot]

Hey professor!

Thanks for submitting this pull request! I'm here to inform the recipients of the pull request that you and the commit authors have already signed the CLA.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. Unfortunately, the Pivotal Tracker project is private so you may be unable to view the contents of the story.

The labels on this github issue will be updated when the story is started.

[animatedmax]

Thank you, professor