Easy coding in online dev environment

[svenefftinge]

This PR adds config to run the Todo app in Gitpod a free online dev environment.
I was helping a user to use Meteor in Gitpod and thought you might be interested in this as well. It will allow anyone to start coding on the example app with a single click.

I configured it so that at start it first runs

• meteor npm install followed by
• meteor

Question: meteor builds the project which takes some time but opens the port immediately. Gitpod listens on ports and opens the preview panel, which then times out because meteor needs a lot of time fro building the app. Is there a command I could run that would do the build? meteor build didn't seem to do the same or I wasn't using the right parameters. Ideally I'd like to have a separate command that builds the app, so that meteor run would work immediately.

[apollo-cla]

@svenefftinge: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Meteor Contributor Agreement here: https://contribute.meteor.com/

[svenefftinge]

You can try the configuration on this PR
https://gitpod.io/#https://github.com/meteor/todos/pull/275

[CLAassistant]

All committers have signed the CLA.

[svenefftinge]

I have signed the CLA