Gem::LoadError for mysql2 gem, but it's already in Gemfile

Question

Gem::LoadError
Specified \'mysql2\' for database adapter, but the gem is not loaded.
Add `gem \'mysql2\'` to your Gemfile

This error occurred while

Answer 1

I have previously installed mysql2 0.4.5 but that was giving me this error so i have installed another version of mysql2 by:

gem install mysql2 --version 0.3.20

Hope this solves your problem.