I have a rails app and I want to deploy it on a server that has a lesser version of rails. What is the simplest way to deploy the app given the difference in version?

• ruby-on-rails

Probably the best approach is to:

1. branch your repository
2. install RVM (Ruby Version Manager)
3. source RVM/restart your shell[s]
4. create an .rvmrc for the version of Ruby on the server
5. adjust the Gemfile to use the version of Rails on the server
6. bundle install
7. fix failing specs/tests
8. manually validate that the site is working as expected

At that point you may want to promote your branch to the new master if you think its likely that the version of Rails on the server won't upgrade soon (or ever).