chore(repo): add description to README.md

README.md

@@ -1,7 +1,20 @@
 ![](./images/banner.png)
 
+<p style="text-align: center"><em>Fully functional API was never an option</em></p>
+
 ---
+
 # GoosyMock
 
-> Fully functional API was never an option
+**GoosyMock** is a configurable test service for mocking HTTP responses,
+featuring SSL support, dedicated administration API and custom payloads
+(binary files that can be served on particular routes). It's also prepared
+for Kubernetes deployments (Helm chart), making it easy to adapt and use.
+
+This project is successor to [**GPTS**](https://github.com/Icikowski/GPTS) and
+was initially meant to be an improvement over existing solution by introducing
+new internal architecture, better approach for serving custom content and
+overall improvements to both code's and repository's structure. Changes turned
+out to be hard to apply, which led to rewriting whole source code from scratch.
 
+[**Explore documentation**](https://icikowski.github.io/GoosyMock)