Added initial issue template

[captainsafia]

Now that GitHub allows you to create templates for issues, I figured it would be a good idea to make one based on the "Submitting a Bug Report" directions in the docs.

Happy to iterate on this.

cc: @willingc

[takluyver]

I don't think this is really the right structure for bugs on the notebook repo, because many (most?) issues are about UI, and don't necessarily involve a code sample. We've been happy enough for years without an issue template, so I don't think we need to rush to create one - it's more important to get something that helps more people than it obstructs.

[Carreau]

+1 an @takluyver comment.

[willingc]

@captainsafia Thanks for thinking about enhancements. I'm not very familiar with GitHub issue templates. Perhaps a good way to go would be try it on a repo that gets less activity than the notebook to see how it works in the wild.

[takluyver]

I'm not very familiar with GitHub issue templates.

I'd be amazed if you were, because Github only launched the feature yesterday ;-)

[willingc]

@takluyver Oh good. I thought perhaps I was living under a rock. ;-)

[Carreau]

I think this does have enough traction (for now).
a better way would be a link in the notebook that uses the following format:

https://github.com/jupyter/notebook/issues/new?title=my%20issue&body=the%20text

To pre-fill the issue with system information. Though we might get too many issues, and so not want to make this too obvious to find.