Add field aliasing support

[alloy]

http://graphql.org/learn/queries/#aliases

[alloy]

A ✨ Ruby option:

artist do
  for_sale_artworks > artworks(for_sale: true)
  not_for_sale_artworks > artworks(for_sale: false)
end

But may be too magical 😊

[mikeyhew]

I was going to suggest a method called alias, but apparently that's a keyword in Ruby.

[mbajur]

does @alloy solution still applies? My client throws

Field 'for_sale_artworks' doesn't exist on type 'Artist'

[yuki24]

@mbajur I don't believe this has ever been implemented. PRs are welcomed.