Initialize rspec
Break up cli into more methods
Use ternary operator instead of if/else
Condense some more lines in CLI
Use heredocs for header and footer
Make write_header and write_footer just return values, and have generate_index responsible for printing them
Add new GitRepo class. Add some helper methods to GitIndex.
Refactor print repo, move puts to process directory
Add instance variable to store file hierarchy. Remove all puts that aren't in generate_index.