As we've added new Gems to this project, we need to change part of the overall project configuration. This is contained in Gemfile, a simple list of Gems used in the project. The old version is as follows:
source :rubygems gem "sinatra" gem "thin"
The first line indicates a standard server for downloading Gems. This server has been deprecated for security reasons, so we'll change it in a moment.
Notice that Gemfile contains a line for the Sinatra Gem, which we referenced in the application, and an additional Gem, thin. This is a simple web server used by the Sinatra framework.
The modified Gemfile incorporates new Gems and a safer source:
source 'http://rubygems.org' gem "sinatra" gem "thin" gem "json" gem "mysql2"
When you modify Gemfile, you must incorporate changes using the following command:
bundle install
If you do not have "bundle" installed, you will have to install that gem before running bundle install. To do this, simply run the following command:
sudo gem install...