[Issue #13] Add render syntactic sugar

[zph]

As in issue #13 an example solution provided by @jrhe an implementation
of said feature has been created.

As per the discussion in the thread this is only a helper to be able to
reach the available options provided in the active_model_serializer gem.

usage is as follows:

get '/some_path' do
  collection = Collection.all
  render collection, { meta: { current_page: 5 }, meta_key: :pagination_info }
end

The return value would be:
{ pagination_info: { current_page: 5 }, collection: [item, item] }

If given without a meta_key it would return as:
{ meta: { current_page: 5 }, collection: [item, item] }

Any feedback appreciated.

@zph, @olleolleolle and @bjoska

[rahilsondhi]

👍 This is very useful.

[rahilsondhi]

Problem: If the collection is empty, the JSON returned is simply [] without metadata. I'm expecting the metadata to still be there even if the collection is empty.

[jrhe]

Not sure if this is the best way to do things but its tested and I haven't had time to redo it myself so I will merge it as people seem to want it.

[bjonord]

Hi @jrhe,
Glad to see this getting merged, but would love to get input on how you would have preferred it to be done? Maybe I can find time to rewrite in a better way given some guidance. 😄

Thanks for taking the time to review and merge it!

[jrhe]

@bjoska, I was thinking that we could somehow proxy ALL options passed to render through to AMS. There are other options like serializer, each_serializer, scope etc which this doesn't support. See issue #13. Haven't looked at the code for a while so I'm not sure how feasible this is. May have some time to look at it next week but if you want to take a look feel free :D.

[bjonord]

@jrhe¸ I'll see what I have time for. Think we had a look at proxying but it didn't pan out as we had hoped. :(