Add Colorful

A curated list of awesome resources to choose your next color scheme.

> Ping me here in a few weeks and I'll reopen ;)

Since then, it hasn't changed much, but as per your advice I've re-opened it :)

Closes #665

readme.md

@@ -423,6 +423,7 @@ Check out my [blog](https://blog.sindresorhus.com) and follow me on [Twitter](ht
 - [Electric Guitar Specifications](https://github.com/gitfrage/guitarspecs) - Checklist for building your own electric guitar
 - [Funny Markov Chains](https://github.com/sublimino/awesome-funny-markov)
 - [Bioinformatics](https://github.com/danielecook/Awesome-Bioinformatics)
+- [Colorful](https://github.com/Siddharth11/Colorful) - Resources to choose your next color scheme.
 
 
 ## License