updated readme

Author: Alexsey-VR

README.md

@@ -3,6 +3,21 @@
 ### Hexlet tests and linter status:
 [![Actions Status](https://github.com/Alexsey-VR/php-project-48/actions/workflows/hexlet-check.yml/badge.svg)](https://github.com/Alexsey-VR/php-project-48/actions) [![check-for-linter](https://github.com/Alexsey-VR/php-project-48/actions/workflows/check-for-linter.yml/badge.svg)](https://github.com/Alexsey-VR/php-project-48/actions/workflows/check-for-linter.yml) [![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=Alexsey-VR_php-project-48&metric=alert_status)](https://sonarcloud.io/summary/new_code?id=Alexsey-VR_php-project-48)
 
+This is a console application that used to compute differences between two .json or .yaml files.
+Output results may be shown to the console in several formats, such that Stylish, Plane or JSON.
+
+To getting start for this application use several steps:
+1. install PHP 8.3 and latest version of the Composer framework;
+2. install required packages:
+$ make install
+3. run application:
+$ bin/gendiff fixtures/file1.json fixtures/file2.json
+
+To print help to the console use command:
+$ bin/gendiff -h
+
+For developers may be used function, that return string result in selected format: 
+
 ### List of functions:
 * [gendiff(string file1, string file2)](https://github.com/Alexsey-VR/php-project-48/blob/main/docs/gendiff.gif)