Could not find gem installed with bundler

For my PHP Symfony Application I need Compass and Sass. Both should be installed in the vendor/bundle folder of my project.

This is what I did so far:

$ gem install bundler
Successfully installed bundler-1.10.6
1 gem installed

$ bundle install --path vendor/bundle
Fetching gem metadata from https://rubygems.org/...........
Fetching version metadata from https://rubygems.org/...
Fetching dependency metadata from https://rubygems.org/..
// ... Installing some gems
Using bundler 1.10.6
Bundle complete! 2 Gemfile dependencies, 10 gems now installed.
Bundled gems are installed into ./vendor/bundle.

Well now it comes to my problem. When i execute one of the installed gems I get the following error:

$ vendor/bundle/ruby/1.9.1/bin/compass 
/usr/local/rvm/rubies/ruby-1.9.3-p551/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:315:in `to_specs': Could not find 'compass' (>= 0) among 30 total gem(s) (Gem::LoadError)
Checked in 'GEM_PATH=/usr/local/rvm/gems/ruby-1.9.3-p551:/usr/local/rvm/gems/ruby-1.9.3-p551@global', execute `gem env` for more information
    from /usr/local/rvm/rubies/ruby-1.9.3-p551/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:324:in `to_spec'
    from /usr/local/rvm/rubies/ruby-1.9.3-p551/lib/ruby/site_ruby/1.9.1/rubygems/core_ext/kernel_gem.rb:64:in `gem'
    from vendor/bundle/ruby/1.9.1/bin/compass:22:in `<main>'

I get that it looks in the $GEM_PATH and of course cannot find it. But how do i resolve this issue? I don't want to change the gem path to the project folder.

Solution

With Bundle you should launch the application with the Bundle Exec command. For launch compass you can do, as example:

$ bundle exec compass watch

$ bundle exec compass compile

Check this nice article about further info.

Hope this help