Set rubocop config with environment variable

[elstgav]

Re-worked from #5:

I'm looking to add this option to support the SublimeLinter plugin I'm writing (see related issue). The main problem I've run into is that while editing your files, SublimeLinter will create a temporary copy to lint. Since the tmp file is in a separate directory, rubocop won't correctly determine the config location (the slim-lint config, however, is manually set).

This would also allow users to keep a separate rubocop configuration for their slim files if they so choose.

As suggested, this pull request lets you set the config with an environment variable.

Things left to do:

• Add a note to the documentation
• Test the functionality. I'm not sure how to set that test up though; would I need to create a dummy .rubocop.yml file?

[sds]

Thanks for the pull request, @elstgav.

I've merged your commit in 15e87b4 with some modifications in bf0a484...9b15cc4, including tests and renaming the variable to SLIM_LINT_RUBOCOP_CONF (to be explicit).

Let me know if there's anything else you need to support the integration with Sublime. If not, I'll cut a new release (would be great if you could test that everything works as expected on your end).

[elstgav]

After learning some more Python and stumbling through getting my environment set up correctly, I can confirm that yes, it does work as expected. Thanks for your help! I'll push out an update to my plugin as soon as you cut the gem.

[sds]

I've just released 0.5.0.