Make sure this package exports something to add subscriptions to Apollo Client

[stubailo]

https://medium.com/apollo-stack/graphql-subscriptions-in-apollo-client-9a2457f015fb#.37xz9hr75

Reported by @mlp5ab from scaphold

[drFabio]

Following the blog now and was searching the code because this part was not working. So the medium post said that there was an exported function that does not exist or the function goes by a different name now? Searched the code for addGraphQLSubscriptions and it reported nothing does this function exist somewhere or the post was an spec ?

[helfer]

@drFabio yeah, it should be here but we forgot to include it. For the time being you can copy-paste it out of GitHunt-React.

[anhldbk]

@helfer Open for a PR against this issue?

[helfer]

@anhldbk yes, definitely!

[Urigo]

Implemented in this PR: #64 (thanks @Darkbladecr), and I will release a new version in the next couple of minutes