Add JavaScript Observables (#659)

> An Observable is a collection that arrives over time. Observables can be used to model push-based data sources such as events, timer intervals, asynchronous requests, and animations. Observables can be transformed, combined, and consumed using array-like methods.

https://github.com/sindresorhus/awesome-observables

readme.md

@@ -83,6 +83,7 @@ Check out my [blog](https://blog.sindresorhus.com) and follow me on [Twitter](ht
 	- [AVA](https://github.com/sindresorhus/awesome-ava) - Test runner
 	- [ESLint](https://github.com/dustinspecker/awesome-eslint)
 	- [Functional Programming](https://github.com/stoeffel/awesome-fp-js)
+	- [Observables](https://github.com/sindresorhus/awesome-observables)
 - [Swift](https://github.com/matteocrippa/awesome-swift)
 	- [Education](https://github.com/hsavit1/Awesome-Swift-Education)
 	- [Playgrounds](https://github.com/uraimo/Awesome-Swift-Playgrounds)