adding handler.before_create/delete/update & after_create/delete/update

[futurist]

do you mind using co/Promise/generator to this lib? I've created this PR to be use as below:

handler.before_create = function(){
  return new Promise(function(resolve, reject){
    resolve()
    //reject('some thing wrong, cannot create')
  })
}

handler.after_create = function(err, doc, next){
  if(err) do_something()
  else do_something_with(doc)

  next && next()
}

[theninj4]

Hi @futurist - I've extended the documentation in jsonapi-server to cover an example project layout. The example handler demonstrates how you might step in and tweak objects before/after a storage handler. I see it as more of a Javascript problem than a framework problem. https://github.com/holidayextras/jsonapi-server/blob/master/documentation/suggested-project-structure.md

[futurist]

thank you! seems it is more standard way. will have a try.
Now the PR is far from the direction and more as a personal way, close for now