Implement adapter

[gr0uch]

I think that this might benefit from an adapter implementation.

var jsonApiAdapter = require('fortune-json-api/adapter')

Some prerequisites:

• Fortune.js needs to read an option on the adapter to disable doing inverse updates.
• Fortune.js needs to read an option on the adapter to disable referential integrity checks.

Referenced in fortunejs/fortune#261

[kketch]

@daliwali yeah, it would be so nice to have it 👍
I have the logical operators things to finish for fortune-postgres, fortune-mongodb, fortune-nedb, and then I would like to address that If no one does