Use https protocol for Github

[aidanharan]

Use the https protocol to connect to Github rather than git. This will remove the following warning message.

$  bundle install
The git source `git://github.com/rails/rails.git` uses the `git` protocol, which transmits data without encryption. Disable this warning with `bundle config git.allow_insecure true`, or switch to the `https` protocol to keep your data secure.
Fetching git://github.com/rails/rails.git
...

I copied the code from the Rails Gemfile https://github.com/rails/rails/blob/master/Gemfile