`method_missing': undefined method `less' 

I use anjlab-bootstrap-rails gem to load Twitter Bootstrap. It's SASS based and doesn't use less-rails. I added `less-rails` as a dependency and load it in your engine to avoid getting this error. It's a dependency after all, not only in development.

```
/home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/railtie/configuration.rb:85:in `method_missing': undefined method `less' for #<Rails::Application::Configuration:0x000000066694e0> (NoMethodError)
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/fuelux-rails-2.3.0/lib/fuelux-rails/engine.rb:8:in `block in <class:Engine>'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
	from /home/mathieu/workspace/voc-terminology-engine/config/environment.rb:5:in `<top (required)>'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
	from /home/mathieu/workspace/voc-terminology-engine/config.ru:3:in `block in <main>'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
	from /home/mathieu/workspace/voc-terminology-engine/config.ru:in `new'
	from /home/mathieu/workspace/voc-terminology-engine/config.ru:in `<main>'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/commands/server.rb:46:in `app'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/commands/server.rb:70:in `start'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/commands.rb:55:in `block in <top (required)>'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
	from /home/mathieu/.rvm/gems/ruby-2.0.0-p0@voc-terminology-engine/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
	from script/rails:6:in `require'
	from script/rails:6:in `<main>'
```