Allow for cache adapter injection

[WyriHaximus]

While developing wyrihaximus/react-cache-redis I've noticed that passing your own cache implementation into the resolver is suboptimal compared to the proposed change.

To do:

• Implement cache adapter injection
• Tests
• Documentation

[WyriHaximus]

@cboden @clue please let me know if you 👍 this idea, if so I'll add the tests and documentation

[clue]

I think this makes sense 👍

[WyriHaximus]

I think this makes sense 👍

Cheers! Does the way I've implemented it also makes sense?

[clue]

Does the way I've implemented it also makes sense?

Absolutely! I'm not a huge fan of the given design, but despite a lack of documentation/tests this LGTM 👍

[WyriHaximus]

Absolutely! I'm not a huge fan of the given design, but despite a lack of documentation this LGTM 👍

Cheers, I'll add the tests and documentation soon

[WyriHaximus]

Documentation and test added, also updated the other cache test to ensure default behavior isn't affected

[clue]

Perhaps we can make this a bit more explicit:

By default, the above will use an in memory cache.

You can also specify a custom cache implementing [`CacheInterface`](https://github.com/reactphp/cache) to handle the record cache instead:

[…]

See also the wiki for possible [cache implementations](https://github.com/reactphp/react/wiki/Users#cache-implementations).

[WyriHaximus]

Done 👍

[clue]

LGTM 👍

[WyriHaximus]

Great!

[WyriHaximus]

Could anyone else 👎 or 👍 this so it can be merged and tagged? Could use that :)

[clue]

Let's get this in!