Add edit resource route

Editing a resource is now possible with a patch request. E.g.: PATCH /articles/5

Add missing prefix to droplet route group

Add route prefix for get group inside the VaporJsonApi Droplet extension.

Add getRelationships function and route

Add getRelationships as described in the jsonapi documentation.

Implement relationship findInModel into resource creation

Use findInModel in order for relationship adding to work properly in the resource creation.

Add findInModel function to relationship models

It was not possible to call find on the type stored in parent, children and siblings model as static functions are statically dispatched. Added a findInModel function to relationships in order to be able to use this function.

First usable POST route

Implemented the first post route with resource creation and relationship creation.

Finalize current relationship structure

This is the finalized draft of the relationship structure as it should be for the next few versions (hopefully...)

Change Parent Model structure

Changed the structure of Parent Model again...

Debug messages

This is just a version with more debug messages

Fix type fetching for resource creation

The type value was fetched from the top level instead of the data object. Fixed that in this release.