Update Docker README

The first example is a quick introduction into how to run the code

Add a second part to demonstrate how to edit the code and then re-create
the database.

Author: oalders

README-Docker.md

@@ -1,5 +1,17 @@
 # Docker README
 
+<!-- vim-markdown-toc GFM -->
+
+* [Getting Started](#getting-started)
+* [Building Your Docker Container](#building-your-docker-container)
+* [Refactoring Your Code](#refactoring-your-code)
+  * [Mapping your local volume to the Docker container](#mapping-your-local-volume-to-the-docker-container)
+  * [Creating the database](#creating-the-database)
+
+<!-- vim-markdown-toc -->
+
+## Getting Started
+
 A `Dockerfile` has been provided in order to make this code more convenient to run. To get started via `Docker`, you'll need:
 
 * A working Docker environment
@@ -17,7 +29,7 @@ docker build . -t mmdb-from-go
 This will build your Docker container, build your `Go` code and also run the example code for you. To log in to your container, run this command. (Linux users may need to preface this command with `sudo`).
 
 ```bash
-docker run -it --volume $(pwd):/project mmdb-from-go:latest /bin/bash
+docker run -it mmdb-from-go:latest /bin/bash
 ```
 
 Once you have logged in, you can test out your freshly created database:
@@ -28,8 +40,19 @@ mmdbinspect -db GeoLite2-Country.mmdb \
 56.0.0.1 56.1.0.0/24 56.2.0.54 56.3.0.1 | less
 ```
 
-You can freely edit the code outside of the Docker container and then re-run it from inside the container:
+## Refactoring Your Code
+
+You can freely edit the code outside of the Docker container and then re-run it from inside the container. To do so, you'll need to map your local volume to the container and then rebuild the database.
 
+### Mapping your local volume to the Docker container
 ```bash
-./mmdb-from-go-blogpost
-```
+docker run -it --volume $(pwd):/project mmdb-from-go:latest /bin/bash
+```
+
+### Creating the database
+
+Once you are logged in to your container, run the following code:
+
+```bash
+go build && ./mmdb-from-go-blogpost
+```