[with-firebase] Ensure server credentials aren't bundled with client code (#1875)

* [with-firebase] Ensure server credentials aren't bundled with client code

* [with-firebase] Fix travis build failure

examples/with-firebase/credentials/client.js

@@ -0,0 +1,3 @@
+module.exports = {
+    // TODO firebase client config
+}

examples/with-firebase/credentials/server.js

@@ -0,0 +1,3 @@
+module.exports = {
+    // TODO firebase server config
+}

examples/with-firebase/firebaseCredentials.js

@@ -1,8 +0,0 @@
-module.exports = {
-  clientCredentials: {
-    // TODO firebase client config
-  },
-  serverCredentials: {
-    // TODO service account json here
-  }
-}

examples/with-firebase/pages/index.js

@@ -1,7 +1,7 @@
 import React, { Component } from 'react'
 import firebase from 'firebase'
 import 'isomorphic-fetch'
-import { clientCredentials } from '../firebaseCredentials'
+import clientCredentials from '../credentials/client'
 
 export default class Index extends Component {
   static async getInitialProps ({req, query}) {

examples/with-firebase/server.js

@@ -10,7 +10,7 @@ const app = next({ dev })
 const handle = app.getRequestHandler()
 
 const firebase = admin.initializeApp({
-  credential: admin.credential.cert(require('./firebaseCredentials').serverCredentials),
+  credential: admin.credential.cert(require('./credentials/server')),
   databaseURL: '' // TODO database URL goes here
 }, 'server')