Extend the persistence layer to support more DB

[roccomuso]

API Example

var WebHooks = require('node-webhooks')
var InMemory = require('webhooks-memory-storage')
var FileStorage = require('webhooks-file-storage')

var webHooks = new WebHooks({
    db: new InMemory(),  // in-memory DB
    //db: new FileStorage('./webHooksDB.json'), // json file that store webhook URLs
    // redis, mongoDB, lokiJS, levelDB etc.
});

WebHooks Storage Implementation

Every webHooks store must be an EventEmitter and implement specific methods. The following methods are the list of required, recommended, and optional.

• Required methods are ones that this module will always call on the store.
• Recommended methods are ones that this module will call on the store if available.
• Optional methods are ones this module does not call at all, but helps present uniform stores to users.

[ccollie]

I know this is years late, but i've started a fork using https://github.com/lukechilds/keyv

[roccomuso]

@ccollie Feel free to PR here using keyv