vim-rails is enabled only if config/environment.rb is present in the Rails working directory.

At work, we have an engine based working directory that does not contain this file (as there’s an embedded application within the engine.)

To enable vim-rails, I need to do:

echo "load ::File.expand_path('../../embedded-app/config/environment.rb',__FILE__)" >> config/environment.rb
mkdir -p .git/info
echo "config/environment.rb" >> .git/info/exclude

Within the repo to enable vim-rails support.