Add deploy to Firebase CDN on template's README (Closes facebook#374)

Author: guilhermebruzzi

Diff for: packages/react-scripts/template/README.md

@@ -54,6 +54,7 @@ You can find the most recent version of this guide [here](https://github.com/fac
   - [Now](#now)
   - [S3 and CloudFront](#s3-and-cloudfront)
   - [Surge](#surge)
+  - [Firebase](#firebase)
 - [Troubleshooting](#troubleshooting)
 - [Something Missing?](#something-missing)
 
@@ -1092,6 +1093,71 @@ Install the Surge CLI if you haven't already by running `npm install -g surge`.
 
 Note that in order to support routers that use HTML5 `pushState` API, you may want to rename the `index.html` in your build folder to `200.html` before deploying to Surge. This [ensures that every URL falls back to that file](https://surge.sh/help/adding-a-200-page-for-client-side-routing).
 
+### Firebase
+
+Install the Firebase CLI if you haven't already by running `npm install -g firebase-tools`.
+
+Sign up for a [Firebase account](https://console.firebase.google.com/) and create a new project.
+
+Run the `firebase login` command and login with your previous created Firebase account.
+
+Then run the `firebase init` command from your project's root. You need to choose the *Hosting: Configure and deploy Firebase Hosting sites* option, choose your previous created project, accept *database.rules.json* to be created, choose *build* as public directory and accept to *Configure as a single-page app* with the *y* option.
+
+```sh
+    === Project Setup
+
+    First, let's associate this project directory with a Firebase project.
+    You can create multiple project aliases by running firebase use --add,
+    but for now we'll just set up a default project.
+
+    ? What Firebase project do you want to associate as default? Example app (example-app-fd690)
+
+    === Database Setup
+
+    Firebase Realtime Database Rules allow you to define how your data should be
+    structured and when your data can be read from and written to.
+
+    ? What file should be used for Database Rules? database.rules.json
+    ✔  Database Rules for example-app-fd690 have been downloaded to database.rules.json.
+    Future modifications to database.rules.json will update Database Rules when you run
+    firebase deploy.
+
+    === Hosting Setup
+
+    Your public directory is the folder (relative to your project directory) that
+    will contain Hosting assets to uploaded with firebase deploy. If you
+    have a build process for your assets, use your build's output directory.
+
+    ? What do you want to use as your public directory? build
+    ? Configure as a single-page app (rewrite all urls to /index.html)? Yes
+    ✔  Wrote build/index.html
+
+    i  Writing configuration info to firebase.json...
+    i  Writing project information to .firebaserc...
+
+    ✔  Firebase initialization complete!
+```
+
+After creating the build folder with `npm run build`, you can deploy to firebase with the `firebase deploy` command.
+
+```sh
+    === Deploying to 'example-app-fd690'...
+
+    i  deploying database, hosting
+    ✔  database: rules ready to deploy.
+    i  hosting: preparing build directory for upload...
+    Uploading: [==============================          ] 75%✔  hosting: build folder uploaded successfully
+    ✔  hosting: 8 files uploaded successfully
+    i  starting release process (may take several minutes)...
+
+    ✔  Deploy complete!
+
+    Project Console: https://console.firebase.google.com/project/example-app-fd690/overview
+    Hosting URL: https://example-app-fd690.firebaseapp.com
+```
+
+For more information see [Add Firebase to your JavaScript Project](https://firebase.google.com/docs/web/setup).
+
 ## Troubleshooting
 
 ### `npm test` hangs on macOS Sierra