Update Readme
Update Readme

Added a way to improve build times by about 10 minutes as mentioned in #184 by @jfcouture
harisadam/ember-cli-rails,rwz/ember-cli-rails,jgadbois/ember-cli-rails,weggesser/ember-cli-rails,seanpdoyle/ember-cli-rails,rwz/ember-cli-rails,johan--/ember-cli-rails,rwz/ember-cli-rails,seanpdoyle/ember-cli-rails,koryteg/glimmer-rails,weggesser/ember-cli-rails,KeenRegard/ember-cli-rails,koryteg/glimmer-rails,weggesser/ember-cli-rails,thoughtbot/ember-cli-rails,Szeliga/ember-cli-rails,seanpdoyle/ember-cli-rails,koryteg/glimmer-rails,thoughtbot/ember-cli-rails,thoughtbot/ember-cli-rails