ReadMe: update contents

Add License, Credits, Screenshot

README.md

@@ -1,5 +1,11 @@
 # GstPipelineStudio: Draw your own GStreamer pipeline ...
 
+## Description
+
+GstPipelineStudio aims to provide a graphical user interface to the GStreamer framework. From a first step in the framework with a simple pipeline to a complex pipeline debugging, the tool provides a friendly interface to add elements to a pipeline and debug it.
+
+![alt tag](data/screenshots/gps_screenshot.png)
+
 ## Setup
 
 Install the Rust toolchain via `rustup`
@@ -32,3 +38,24 @@ dnf install gtk4-devel gstreamer1-devel gstreamer1-plugins-base-devel python3-pi
 meson builddir
 cargo run
 ```
+
+## License
+
+GstPipelineStudio is distributed under the terms of the GPL3 license.
+See LICENSE for more information.
+
+## Credits
+
+GstPipelineStudio wouldn't exist without free and open-source software such as
+GLib, GStreamer, GTK and many more.
+
+This project has been also possible thanks to amazing projects such as:
+
+- [pipeviz](https://github.com/virinext/pipeviz)
+- [helvum](https://gitlab.freedesktop.org/ryuukyu/helvum)
+
+## Contributing
+
+Every contribution is greatly appreciated! You will just need a [gitlib account](https://gitlab.freedesktop.org/users/sign_in?redirect_to_referer=yes). [Fork](https://docs.gitlab.com/ee/user/project/repository/forking_workflow.html) this repo, [clone](http://git-scm.com/docs/git-clone) your fork, create a [feature branch](https://www.google.com/search?q=git+feature+branches), [commit](http://git-scm.com/docs/git-commit), [push](http://git-scm.com/docs/git-push) and submit a [merge request](https://docs.gitlab.com/ee/user/project/merge_requests/creating_merge_requests.html).
+
+Submit any suggestions, questions or bugs to the [Issue Tracker](https://gitlab.freedesktop.org/dabrain34/GstPipelineStudio/-/issues/).