Add useful resources

[Granze]

We should provide a list of links to useful resources to learn JS.

[kamerontanseli]

Hi,

I can actually help with that:

Beginner

• http://jstherightway.org/
• http://diveintohtml5.info/index.html
• http://www.javascriptenlightenment.com/JavaScript_Enlightenment.pdf
• http://speakingjs.com/es5/
• http://exploringjs.com/es6/

Intermediate

• https://leanpub.com/understandinges6/read/
• https://github.com/tcorral/javascript-challenges-book
• http://domenlightenment.com/
• http://read.humanjavascript.com/ch01-introduction.html