Enable gitpod integration

[restlessronin]

Hi @nicbet ,

I recently did a gitpod integration for a phoenix project I'm working on, and wanted to make it public. Rather than create a separate project which is very similar to this one, I thought it would be better to contribute it here. The project would then conceptually have integrations with various "dev container" implementations (like the VS Code integration).

I've simplified the integration so that it will work with the existing project structure and docker-compose files.

I hope it makes sense for you to add it.

[nicbet]

Very cool, just tried it out from your fork.

However, I can't save a file from the IDE

Does the .gitpod.yml or Dockerfile need any changes to user or user permissions to work with Gitpod?

[restlessronin]

I don't believe the .gitpod.yml or the Dockerfile have anything to do with the permissions for saving. I think there's some kind of credential exchange handshake between gitpod and github that enables the saving. Let me take a look at it from my end.

[restlessronin]

You have to install the Gitpod.io app in github with the correct permissions.

https://github.com/apps/gitpod-io

[restlessronin]

I got this error message when I tried to save a file to the docker-phoenix repo

> git push origin enable-gitpod:enable-gitpod
remote: error: GH007: Your push would publish a private email address.        
remote: You can make your email public or disable this protection by visiting:        
remote: http://github.com/settings/emails        
To https://github.com/restlessronin/docker-phoenix.git
 ! [remote rejected] enable-gitpod -> enable-gitpod (push declined due to email privacy restrictions)
error: failed to push some refs to 'https://github.com/restlessronin/docker-phoenix.git'

I know github has some privacy feature where committer emails are not visible publicly and are proxied through a github generated alias. That may be an additional issue here.

[restlessronin]

Is there anything else that should be addressed in this PR?