Capistrano 3 deploy failure - Rails 3.2

I've got a Rails app that I deploy using capistrano 3. The app has deployed successfully for over a year now but today after making a few changes to html files the deployment fails with the following message:

no ruby in PATH/CONFIG
 DEBUG [a202e059] 
 DEBUG [a202e059]       /home/takebackdemo/.rbenv/versions/2.1.0/bin/ruby /home/takebackdemo/apps/TakeBackDMS_development/shared/bundle/ruby/2.1.0/bin/rake assets:precompile:all RAILS_ENV=developm
ent RAILS_GROUPS=assets
 DEBUG [a202e059] 
 DEBUG [a202e059]       rake aborted!
 DEBUG [a202e059]       Command failed with status (1): [/home/takebackdemo/.rbenv/versions/2.1.0/b...]
 DEBUG [a202e059]       /home/takebackdemo/apps/TakeBackDMS_development/shared/bundle/ruby/2.1.0/gems/actionpack-3.2.13/lib/sprockets/assets.rake:12:in `ruby_rake_task'
/home/takebackdemo/apps/TakeBackDMS_development/shared/bundle/ruby/2.1.0/gems/actionpack-3.2.13/lib/sprockets/assets.rake:21:in `invoke_or_reboot_rake_task'
/home/takebackdemo/apps/TakeBackDMS_development/shared/bundle/ruby/2.1.0/gems/actionpack-3.2.13/lib/sprockets/assets.rake:29:in `block (2 levels) in <top (required)>'
 DEBUG [a202e059]       Tasks: TOP => assets:precompile
 DEBUG [a202e059]       (See full trace by running task with --trace)
(Backtrace restricted to imported tasks)

As I said, the only changes I made were to a few html files. When I run ruby -v I get:

ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-darwin13.0]

Why would this happen?