Refactor README to split production/development environments
Created by: cabello
As suggested in https://github.com/gitlabhq/gitlab-vagrant-vm/issues/22 I made some changes to README.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Created by: cabello
As suggested in https://github.com/gitlabhq/gitlab-vagrant-vm/issues/22 I made some changes to README.