Suggest Discourse in issue template

[manics]

See #1230 (comment)

Can move this discussion to http://discourse.jupyter.org/ (where most of the people who hang out here also hang out, as well as more people). We are trying to streamline the different discussion places and want to use the issues on GitHub repos for technical discussions on how to change the contents of the repo. More general discussions should go to discourse so that they are easier to find, better indexed by google and generally more accessible than being hidden in the bowls of a GitHub repository ;)

I thought it'd be useful to mention Discourse in the issue template.

[betatim]

Looks good to me! I left one comment about removing or moving the mention of gitter.

[betatim]

Thanks a lot for helping out with keeping the gears of the contribution machine well oiled.

[consideRatio]

@manics ❤️ you are doing so much great stuff!!!