development.js

// config/development.js
module.exports = {
  NAME: 'FirestackDemo.dev',
  firestack: {
    apiKey: "XXXXXXXX",
    authDomain: "your-auth-domain.firebaseapp.com",
    databaseURL: "https://your-database-url.firebaseio.com",
    storageBucket: "your-storage-bucket.appspot.com",
  }
}

environment.js

// In config/environment.js
let defaultEnv = {
  NAME: 'FirestackDemo'
}

let env = {}
if (process.env.NODE_ENV === 'development') {
  env = require('./development')
}

module.exports = Object.assign({}, defaultEnv, env);