When I released my first ruby gem for rspec test suite parallelisation I decided to write a short blog post about it. If you don't have your own blog you can write the post on your company blog. Thanks to that you will get some promotion because your company or colleagues can tweet or share it on Facebook.

Another thing I did was to post my article on Reddit in the ruby group. This seems to be a validated way of getting some traction. Make sure your friend read the blog post before publishing so you can iterate after feedback to make it interesting for people who will first time hear about your tool. :)

Oh, and here is my blog post: http://blog.lunarlogic.io/2014/parallel-your-specs-and-dont-...