Development container

Development container that can be used with VSCode.

It works on Linux, Windows and OSX.

Requirements

Create the following files and directory on your host if you don't have them:
```
touch ~/.gitconfig ~/.zsh_history
mkdir -p ~/.ssh
```
For Docker on OSX: ensure the project directory and your home directory ~ are accessible by Docker.
Open the command palette in Visual Studio Code (CTRL+SHIFT+P).
Select Dev Containers: Open Folder in Container... and choose the project directory.

For customizations to take effect, you should "rebuild and reopen":

Customizations available are notably:

Extend the Docker image in Dockerfile. For example add curl to it:
```
FROM qmcgaw/godevcontainer
RUN apk add curl
```
Changes to VSCode settings and extensions in devcontainer.json.
Change the entrypoint script by adding a bind mount in devcontainer.json of a shell script to /root/.welcome.sh to replace the current welcome script. For example:
```
// Welcome script
{
    "source": "./.welcome.sh",
    "target": "/root/.welcome.sh",
    "type": "bind"
},
```
Change the vscode service container configuration either in docker-compose.yml or in devcontainer.json.
Add other services in docker-compose.yml to run together with the development VSCode service container. For example to add a test database:
```
  database:
    image: postgres
    restart: always
    environment:
      POSTGRES_PASSWORD: password
```
More customizations available are documented in the devcontainer.json reference.