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

Being Beginner to the ruby i could not figure out the line gem 'mysql2', '~> 0.3.18'

it simply means go to your rails project folder and then there is line for mysql2 it will be like 0.4* so you can change it to gem 'mysql2', '~> 0.3.18'

and as we have new definition, we have to rebuild the dependency so to do that simple command as explained on the top bundle install