If you are facing the following error
Failed to build gem native extension
While installing gems on ubuntu. Please refer to this link for a solution to solve the error.
This error usually occurs when installing gems like mysql and nokogiri.
Thanks a bunch for sharing the solution. I've just got this issue when working on the project from http://yourhomeworkhelp.org/do-my-calculus-homework/ but now I think I can manage to solve it and continue with my work. Again, a huge thank you!