refs https://github.com/TryGhost/Toolbox/issues/522
- API-level response caching allows to cache responses bypassing the "pipeline" processing
- The main usecase for these caches is caching GET requests for expensive Content API requests
- To enable response caching add a "cache" key with a cache instance as a value, for example for posts public cache configuration can look like:
```
module.exports = {
docName: 'posts',
browse: {
cache: postsPublicService.api.cache,
options: [ ...
```
refs https://github.com/TryGhost/Toolbox/issues/363
- this API framework is standalone and should be pulled out into a
separate package so we can define its boundaries more clearly, and
promote better testing of smaller parts
