README update

Author: teamon

README.md

@@ -1,19 +1,20 @@
 # mix docker
 
-Put your Elixir app inside minimal docker image based on alpine linux.
-Based on distillery releases.
+Put your Elixir app inside minimal Docker image.
+Based on [alpine linux](https://hub.docker.com/r/bitwalker/alpine-erlang/)
+and [distillery](https://github.com/bitwalker/distillery) releases.
 
 ## Installation
 
   1. Add `mix_docker` to your list of dependencies in `mix.exs`:
 
     ```elixir
     def deps do
-      [{:mix_docker, "~> 0.2.2"}]
+      [{:mix_docker, "~> 0.3.0"}]
     end
     ```
 
-  2. Configure docker image name
+  2. Configure Docker image name
 
     ```elixir
     # config/config.exs
@@ -22,6 +23,14 @@ Based on distillery releases.
 
   3. Run `mix docker.init` to init distillery release configuration
 
+  4. Run `mix docker.build` & `mix docker.release` to build the image. See [Usage](#Usage) for more.
+
+
+## Guides
+
+- [Getting Started Tutorial](http://teamon.eu/2017/deploying-phoenix-to-production-using-docker/)
+- [Setting up cluster with Rancher](http://teamon.eu/2017/setting-up-elixir-cluster-using-docker-and-rancher/)
+
 ## Usage
 
 ### Build a release
@@ -35,3 +44,44 @@ Run `mix docker.publish` to push newly created image to docker registry
 
 ### All three in one pass
 Run `mix docker.shipit`
+
+### Customize default Dockerfiles
+Run `mix docker.customize`
+
+
+## FAQ
+
+#### How to configure my app?
+
+Using ENV variables.
+The provided Docker images contain `REPLACE_OS_VARS=true`, so you can use `"${VAR_NAME}"` syntax in `config/prod.exs`
+like this:
+
+```elixir
+config :hello, Hello.Endpoint,
+  server: true,
+  url: [host: "${DOMAIN}"]    
+
+config :hello, Hello.Mailer,
+  adapter: Bamboo.MailgunAdapter,
+  api_key: "${MAILGUN_API_KEY}"
+```
+
+
+#### How to attach to running app using remote_console?
+
+The easiest way is to `docker exec` into running container and run the following command,
+where `CID` is the app container IO and `hello` is the name of your app.
+
+```bash
+docker exec -it CID /opt/app/bin/hello remote_console
+```
+
+
+#### How to install additional packages into build/release image?
+
+First, run `mix docker.customize` to copy `Dockerfile.build` and `Dockerfile.release` into your project directory.
+Now you can add whatever you like using standard Dockerfile commands.
+Feel free to add some more apk packages or run some custom commands.
+TIP: To keep the build process efficient check whether a given package is required only for
+compilation (build) or runtime (release) or both.