refs https://github.com/TryGhost/Toolbox/issues/515
- We don't have a good way to test TTL caches without setting up Redis in the environment
- Adding in-memory cache adapter with TTL allows to run tests on CI without having to install Redis
- Also, TTL in memory cache can be a great substitution for Redis-based caches on instances that
have a lot of spare RAM and don't need to use Redis necessarily
- MemoryTTL cache accepts two parameters "TTL" and "max"
- TTL - is time in milliseconds to hold the value for in cache
- max - is the maximum amount of items to keep in the cache
- To use MemoryTTL cache specify following config in the cache section:
```
"adapters": {
"cache": {
"imageSizes": {
"adapter": "MemoryTTL",
"ttl": 3600
}
}
}
```
- Above config would apply MemoryTTL cache to imageSizes feature with TTL fo 3600 ms
