Rails -v says I'm running 3.0, but I need to run 2.1.1 to get this app installed

Question

I tried to do:

rake db:migrate

to get this app from github installed on my mac, and I got this error:

Missing the Rails 2.1.1 gem. Please `gem install -v=2.1.1 rails`, update your RAILS_GEM_VERSION setting in config/environment.rb for the Rails version you do have installed, or comment out RAILS_GEM_VERSION to use the latest version installed.

how can I temporarily or for this app only run 2.1.1.?

Answer 1

it is best to use RVM if you use Mac OS X or Ubuntu.

simply create another gemset

rvm install 1.8.7    or whatever Ruby version
rvm 1.8.7
rvm gemset create rails2.1.1
rvm gemset use rails2.1.1
gem install -v 2.1.1 rails
rails -v

and now you will be using rails 2.1.1. You can create other gemsets, and also use rvm 1.8.7@rails238 to change to the Ruby with the gemset. You can also install Ruby 1.9.2 like the first line above and create different gemsets as well.

Answer 2

In case you're not using RVM, just do what the error message says. Execute $ gem install -v=2.1.1 rails then you're good to go.