Every now and then you might see an error in your rails application that says it can’t include something. For instance, if you are working with handlebars in your asset pipeline you may get a Can't include handlebars.vm error.

Most of the time this is caused by a mismatch in libraries by running bundle update instead of bundle install on a project. To get yourself back to the right version checkout the original Gemfile.lock file. Using git you can run the following:

git checkout origin/master Gemfile.lock
bundle 

Running an bundle update overrides the Gemfile.lock and may break version compatibility with other gems. To be on the safe side always run bundle which defaults to bundle install.