Fix bundler errors when running `bowl`

Sometimes the bowl command is not correctly installed on the VM. If you get an error like:

$ bowl frontend
bash: bowl: command not found

In other ruby applications this type of error can be solved by running the command via bundle exec which load the application’s Gemfile and makes sure all the commands from the dependencies listed in there are available. In this case however, bowl should be globally available, and running it via bundle exec means we can’t change the ruby version it will use to run each different app. Leading to errors like:

/usr/lib/rbenv/versions/2.4.0/bin/bundle:22:in `load': cannot load such file -- /usr/lib/rbenv/versions/1.9.3-p550/lib/ruby/gems/1.9.1/gems/bundler-1.7.4/lib/gems/bundler-1.7.4/bin/bundle (LoadError)

or

/usr/lib/rbenv/versions/1.9.3-p550/lib/ruby/gems/1.9.1/gems/bundler-1.7.4/lib/bundler/source/git.rb:188:in `rescue in load_spec_files': https://github.com/alphagov/mongoid_rails_migrations (at avoid-calling-bundler-require-in-library-code-v1.1.0-plus-mongoid-v5-fix) is not yet checked out. Run `bundle install` first. (Bundler::GitError)

To make bowl globally available reinstall it:

$ cd /var/govuk/govuk-puppet/development-vm
$ sudo gem install bowler
$ rbenv rehash

You should now be able to use bowl to run the apps correctly.

However, if you are seeing an error such as rbenv: cannot rehash: /usr/lib/rbenv/shims/.rbenv-shim exists but the .rbenv-shim file doesn’t exist, try rebooting the VM. Use vagrant halt, vagrant up and then vagrant ssh and hopefully bowl should be globally available.