How to work with the console and github ruby projects

How to work on the console when you have a ruby project you want to try? If you are tweaking the code I believe that gem install … is not the solution.

So, I found a solution here:

What you can do is 

irb -Iname_of_libfolder -rname_of_rb_file

for example for me that was irb -Ilib -rwp_rpc