Update README

Author: a2

README.md

@@ -1,15 +1,15 @@
 # Passcards
 
-A simple Wallet (née Passbook) server. This is a Swift re-implementation of the original [Parse-backed version](https://github.com/a2/passcards-parse).
+A simple [Wallet](https://developer.apple.com/wallet/) server that implements the [PassKit Web Service](https://developer.apple.com/library/content/documentation/PassKit/Reference/PassKit_WebService/WebService.html) requirements. (This is a Swift re-implementation of the original [Parse-backed version](https://github.com/a2/passcards-parse).)
 
-## Usage
+## Building
 
 ```sh
 $ swift build -c release
 $ .build/release/App
 ```
 
-**Environment:**
+## Required Environment
 
 | Key | Description |
 | --- | ----------- |
@@ -28,10 +28,99 @@ $ .build/release/App
 | S3_SECRET_KEY | S3 access secret key |
 | UPDATE_PASSWORD | Update password *(unset == unlimited access)* |
 
+## Deployment
+
+1. Create an app on Heroku
+
+    ```sh
+    $ heroku apps:create [NAME]
+    ```
+
+2. Set the environment variables (as described above)
+
+    ```sh
+    $ heroku config:set X=abc Y=def Z=ghi ...
+    ```
+
+    If you use the [Heroku PostgreSQL](https://devcenter.heroku.com/articles/heroku-postgresql) plugin, you will need to add the plugin (which sets the `DATABASE_URL` environment variable) and then set the required `PG_*` variables.
+
+3. Install the [Container Registry Plugin](https://devcenter.heroku.com/articles/container-registry-and-runtime)
+
+    ```sh
+    $ heroku plugins:install heroku-container-registry
+    ```
+
+4. Build and deploy Docker image to Heroku
+
+    ```sh
+    $ heroku container:push web
+    ```
+
+5. Open the website (a static single-page site)
+
+    ```sh
+    $ heroku open
+    ```
+
+## Usage
+
+### Creating a Pass
+
+This is beyond the scope of the project, but recommended reading includes:
+
+- Wallet Developer Guide: [Building Your First Pass](https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/PassKit_PG/YourFirst.html#//apple_ref/doc/uid/TP40012195-CH2-SW1), [Pass Design and Creation](https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/PassKit_PG/Creating.html#//apple_ref/doc/uid/TP40012195-CH4-SW1)
+- [PassKit Package Format Reference](https://developer.apple.com/library/content/documentation/UserExperience/Reference/PassKit_Bundle/Chapters/Introduction.html)
+
+You will want to set _https://my-heroku-app.herokuapp.com/_ as the `webServiceURL` root key in your _pass.json_.
+
+Example passes, as well as the source of a command-line tool for signing Pass bundles (_signpass_), can be found [here](https://developer.apple.com/services-account/download?path=/iOS/Wallet_Support_Materials/WalletCompanionFiles.zip).
+
+### Uploading a Pass
+
+```sh
+$ curl -X POST \
+    -H "Authorization: Bearer MY_UPDATE_PASSWORD" \
+    -F "pass=@a_local_file.pkpass" \
+    -F "authentication_token=AUTHENTICATION_TOKEN" \
+    -F "pass_type_identifier=PASS_TYPE_IDENTIFIER" \
+    -F "serial_number=SERIAL_NUMBER" \
+    https://my-heroku-app.herokuapp.com/VANITY_URL.pkpass
+```
+
+In the above cURL command, _a_local_file.pkpass_ is a file in the current working directory. Set the `authentication_token`, `pass_type_identifier`, and `serial_number` fields to their corresponding values from the pass's _pass.json_. _MY_UPDATE_PASSWORD_ is the `UPDATE_PASSWORD` environment variable set in your app.
+
+### Updating a Pass
+
+```sh
+$ curl -X PUT \
+    -H "Authorization: Bearer MY_UPDATE_PASSWORD" \
+    -F "pass=@a_local_file.pkpass" \
+    https://my-heroku-app.herokuapp.com/VANITY_URL.pkpass
+```
+
+_a_local_file.pkpass_ is the new local file to replace on the server. _MY_UPDATE_PASSWORD_ is the same `UPDATE_PASSWORD` as above.
+
+### Sharing a Pass
+
+A Pass recipient can go to *https://my-heroku-app.herokuapp.com/VANITY_URL.pkpass* to receive your pass.
+
 ## Author
 
 Alexsander Akers, [email protected]
 
+### My Personal Set-up
+
+On my personal website (*https://pass.a2.io*), I use [CloudFlare](https://www.cloudflare.com) to secure the website subdomain that points to Heroku because then I get TLS / HTTPS (which is required for PassKit in production) for free, because I'm cheap. To that extent, I also use Heroku's free PostgreSQL plan and the [free dyno hours](https://devcenter.heroku.com/articles/free-dyno-hours).
+
+A sleeping-when-idle Heroku app is *perfect* for Wallet services because an iOS device will call your service endpoints in the background and retry upon timeout.
+
+Your app service service is only woken...
+
+1. when someone adds a pass (triggering a pass registration).
+2. when someone deletes a pass (triggering pass de-registration).
+3. when someone triggers a manual refresh of a pass.
+4. when someone toggles "Automatic Updates" on the backside of a pass (shown with the ⓘ button).
+
 ## License
 
 Passcards is available under the MIT license. See the LICENSE file for more info.