Added astro-rust

Added a section for astronomy and astro-rust under it.

README.md

@@ -15,6 +15,7 @@ The goal is to have only projects that are mostly stable and useful to users.
     - [Profiling](#profiling)
     - [Testing](#testing)
   - [Libraries](#libraries)
+    - [Astronomy](#astronomy)
     - [Asynchronous](#asynchronous)
     - [Audio](#audio)
     - [Authentication](#authentication)
@@ -131,6 +132,9 @@ See also [http://areweideyet.com/](http://areweideyet.com/) and [Rust and IDEs](
 
 ## Libraries
 
+### Astronomy
+* [saurvs/astro-rust](https://github.com/saurvs/astro-rust) — a library of algorithms for accurate astronomical calculations [<img src="https://travis-ci.org/saurvs/astro-rust.svg?branch=master">](https://travis-ci.org/saurvs/astro-rust)
+
 ### Asynchronous
 
 * [zonyitoo/coio-rs](https://github.com/zonyitoo/coio-rs) — a coroutine I/O library with a working-stealing scheduler [<img src="https://travis-ci.org/zonyitoo/coio-rs.svg?branch=master">](https://travis-ci.org/zonyitoo/coio-rs)