Added installation instruction

Author: grogy

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Added downloading per month badge from [@grogy](https://github.com/grogy).
 - Added license badge from [@grogy](https://github.com/grogy).
+- Added instruction for installation from [@grogy](https://github.com/grogy).
 
 ## [0.3] - 2020-05-14
 

README.md

@@ -9,4 +9,10 @@ Simple library for creating colored console ouput.
 
 See `example.php` how to use this library.
 
-![Example from Windows 10](https://user-images.githubusercontent.com/89590/40762008-687f909a-646c-11e8-88d6-e268a064be4c.png)
+![Example from Windows 10](https://user-images.githubusercontent.com/89590/40762008-687f909a-646c-11e8-88d6-e268a064be4c.png)
+
+## Installation
+
+Just run the following command to install it:
+
+    composer require php-parallel-lint/php-console-color