Contribute docsets to Dash

[Kapeli]

I've set up a repo where users can contribute docsets to Dash. You can check it out at https://github.com/Kapeli/Dash-User-Contributions. It should contain all the info you need to get started.

Docsets that are contributed in this way will appear in a separate User Contributed section under Dash's Preferences > Downloads (i.e. just like the current Ruby Gems or Cocoa Pods sections).

If you need any help with this, don't hesitate to contact me. Thank you!