Johns Hopkins University Ruby on Rails: An Introduction. Week1 a coursera course. The main objective is to fix the Gemfile Sqlite3 error.
The most important step: Go to This PC open your drive C and you should see the sites folder and open it. You will see the test_install file and open the Gemfile with sublime text and replace line 12 from gem 'sqlite' to gem 'sqlite3', '1.3.13' and press save!