Support all firebase method for saving data

[RainerAtSpirit]

It looks like that currently firebase-aurelia add only implements firebase push method.

https://github.com/PulsarBlow/aurelia-firebase/blob/master/src/collection.js#L23

add(item:any) : Promise {
    return new Promise((resolve, reject) => {
      let query = this._query.ref().push();
      query.set(item, (error) => {
        if (error) {
          reject(error);
          return;
        }
        resolve(item);
      });
    });
  }

It would be useful to support the other methods like set update transaction as well.
https://www.firebase.com/docs/web/guide/saving-data.html

[PulsarBlow]

Hi @RainerAtSpirit

set and update are planned for the next release (0.3.0-beta)

Other advanced features like transaction, query filters/limits are on the roadmap too and will be release in a future version.