InfoMapping.py: Add mappings for Gruntfile.js

[satwikkansal]

Gruntfile.js can contain some bear specific setting values (like ignore paths and include paths) which we can use in coala-quickstart.

[shreyateeza]

@satwikkansal Please elaborate more on this issue. :)

[satwikkansal]

Alright.

https://github.com/coala/coala-quickstart/blob/master/coala_quickstart/generation/InfoMapping.py currently contains mappings for the .editorconfig file.

This might help with concept of mapping in case there's some confusion.

And the info regarding what setting values can be deduced from Gruntfile.js can be found here.

This is a slightly complicated task as it involves combining different pieces, so it'd be great if anyone doing this should discuss the approach before diving into implementation.