Component generator

[Spone]

Let's add a generator, similar to the Rails' one (rails generate component button).

It could be used as: bundle exec middleman component button

We can draw inspiration from https://github.com/middleman/middleman-blog/blob/master/lib/middleman-blog/commands/article.rb

[florentferry]

The component generator should create:

• a component directory inside frontend/components with:
  • [component_name]_component.rb
  • [component_name].slim
  • [component_name].css
  • [component_name].js
• append import "components/[component_name]/[component_name]" into frontend/components/index.js