Welcome to the Fixelpuckers repository. I will try and include some instructions on how to use bitbucket to clone the app to your machine so you can work on it!
You'll have to make sure you have Ruby on Rails setup on your machine. To learn how to setup Rails on 10.5 visit here:
You will also need a copy of Mercurial to grab the application and manage it in the future. There are packages for Mercurial on OS X here:
Download the package for your version of OS X, and install the package. Once installed you can verify a successful installation by typing:
You should get the version information plus a list of commands if all went well.
Once Mercurial is up and running, navigate to where you want your copy of the application to be downloaded in your terminal, then type:
hg clone https://firstname.lastname@example.org/jklina/fixelpuckers/
Mercurial will now download the latest version of the application to your computer, and you should be ready to go.