Add BatchLoader as an adapted Ruby implementation

[exAspArk]

If you port DataLoader to another language, please open an issue to include a link from this repository.

Hi,

I recently created BatchLoader – an adapted Ruby implementation of DataLoader.

The primary difference is that BatchLoader doesn't use Promises, which are not so popular in Ruby since it doesn't have an asynchronous nature. Instead, BatchLoader uses the idea of "lazy" objects which are used in the Ruby standard library.

In addition to the detailed description in README, I wrote a blog post about batching in Ruby, which also describes the gem.

[coveralls]

Coverage remained the same at 100.0% when pulling d08abd6 on exAspArk:batch-loader into 25cf990 on facebook:master.

[wincent]

Thanks @exAspArk. While this isn't so much an "Other implementation" as a different solution in the same problem space, I think it's reasonable to include here given that the differences are explicitly called out in the README, and you include a GraphQL example, which is nice.

[exAspArk]

@wincent thank you! 🙌