Chore/remove rails from required libraries

[EmCousin]

This PR will close #11

• Removing an unnecessary call to rails. We're keeping Rails as a development dependency at the moment
• Fixed potential security issue with Nokogiri
• Provides a more intuitive ability to use a custom serializer when rendering an object

[spijet]

I see a weird error when sending a hash with an empty array inside as a response — the app catches a NoMethodError in the Formatter class. Is it expected?
Please check this gist for minimal app code and log.

[EmCousin]

@spijet Interesting. After digging a bit it appears that a forked version fixed that: cartedo@79049c1

I'll see for updating the PR with adapted testing cover

[spijet]

Yep, this seems to fix the problem with empty arrays.

I also ran into a problem with fast_jsonapi_serializable() method, but it's caused by my own stuff — the app relies on module namespacing, so all serializer classes are named as AppName::Serializers::<Model> instead of <Model>Serializer. I'll probably just rewrite the method to make it work with this scheme and bundle it as an extended class. :)

[spijet]

Actually, I was wrong, and my app does use <Model>Serializer classes, but it still holds them in AppName::Serializers:: namespace. So, here's what worked for me in the end:

def serializable_class(object)
  object = object.first if object.is_a?(Array)
  klass = object.model_name.name.split('::').last
  format('%<klass>sSerializer', klass: klass).safe_constantize
end

It probably won't work for everyone, as it (most likely) relies on auto-loading and auto-resolving magic made possible by Zeitwerk gem, but at least it won't fail on non-namespaced classes.

[spijet]

A little addition to my take on serializable_class() — in case ActiveSupport is available, we can use ActiveSupport::Inflector.demodulize method to make it cleaner. But its usefulness is questionable, since it does almost the same thing (that is, drops everything up until after last :: in given String object). :)

[spijet]

This is exactly what I wanted to propose later today! :D Thank you so much!!

[spijet]

I have converted my app to use Grape and grape_fast_jsonapi for its API and it works perfectly in production environment. Thank you so much! :)