Add cookbook for docker (#215)

* Add cookbook for docker

* Apply suggestions from code review - test code snippet using docs-checker

Author: lwronski

examples/scala-docker/HelloDocker.scala

@@ -0,0 +1,5 @@
+// File was generated from based on docs/cookbooks/scala-docker.md, do not edit manually!
+
+object HelloDocker extends App {
+    println("Hello from Docker")
+}

examples/scala-docker/README.md

@@ -0,0 +1,56 @@
+<!--
+  File was generated from based on docs/cookbooks/scala-docker.md, do not edit manually!
+-->
+
+
+# Package Scala application as a docker image
+
+ScalaCLI can create an executable application and package it into a docker image.
+
+Here is a simple piece of code that will be executed in the docker container.
+
+```scala title=HelloDocker.scala
+object HelloDocker extends App {
+    println("Hello from Docker")
+}
+```
+
+Passing `--docker` to the `package` sub-command generates a docker image. The docker image name parameter `--docker-image-repository` is mandatory.
+
+The following command will generate `hello-docker` image with `latest` tag:
+
+```bash
+scala-cli package --docker HelloDocker.scala --docker-image-repository hello-docker
+```
+
+<!-- Expected:
+Started building docker image with your application, it would take some time
+Built docker image, run it with
+  docker run hello-docker:latest
+-->
+
+```bash
+docker run hello-docker
+# Hello from Docker
+```
+
+<!-- Expected:
+Hello from Docker
+-->
+
+It is also supported to package your app in `JS` or `Native` environments.
+
+```bash
+scala-cli package --js --docker HelloDocker.scala --docker-image-repository hello-docker
+```
+<!-- Expected:
+Started building docker image with your application, it would take some time
+Built docker image, run it with
+  docker run hello-docker:latest
+-->
+
+Package scala native application to docker image is supported only on Linux.
+
+```bash ignore
+scala-cli package --native --docker HelloDocker.scala --docker-image-repository hello-docker
+```

website/docs/cookbooks/scala-docker.md

@@ -0,0 +1,56 @@
+---
+title: Package Scala application as a docker image
+sidebar_position: 5
+---
+
+# Package Scala application as a docker image
+
+ScalaCLI can create an executable application and package it into a docker image.
+
+Here is a simple piece of code that will be executed in the docker container.
+
+```scala title=HelloDocker.scala
+object HelloDocker extends App {
+    println("Hello from Docker")
+}
+```
+
+Passing `--docker` to the `package` sub-command generates a docker image. The docker image name parameter `--docker-image-repository` is mandatory.
+
+The following command will generate `hello-docker` image with `latest` tag:
+
+```bash
+scala-cli package --docker HelloDocker.scala --docker-image-repository hello-docker
+```
+
+<!-- Expected:
+Started building docker image with your application, it would take some time
+Built docker image, run it with
+  docker run hello-docker:latest
+-->
+
+```bash
+docker run hello-docker
+# Hello from Docker
+```
+
+<!-- Expected:
+Hello from Docker
+-->
+
+It is also supported to package your app in `JS` or `Native` environments.
+
+```bash
+scala-cli package --js --docker HelloDocker.scala --docker-image-repository hello-docker
+```
+<!-- Expected:
+Started building docker image with your application, it would take some time
+Built docker image, run it with
+  docker run hello-docker:latest
+-->
+
+Package scala native application to docker image is supported only on Linux.
+
+```bash ignore
+scala-cli package --native --docker HelloDocker.scala --docker-image-repository hello-docker
+```