json - Rails API / Ember-cli web app: what is the conventional workflow? -

in process of building spa, opted combination of rails api , ember-cli.

from understand, architecture of app following:

• rails api run back-end of app, api
• ember-cli run front-end of app, front-end mv* framework
• data served rails api ember-cli json

what not seem clear though, should development workflow?

in other words, should we:

1. build back-end (rails models, etc), build front-end , connect both?
2. build @ same time, 1 feature @ time?
3. go option?

i recommend building both @ same time, in separate apps (that way can test api actual api rather backend), in close proximity 1 another. way can make sure both play nicely each other , you're getting results need, plus if on 1 causes error on other bug become apparent.

let me know if answers question enough, can clarify/ give additional examples here if you'd like.