add small description of the tool in the README

Author: lukaspie

README.md

@@ -1,6 +1,11 @@
 # nomad-north-vesta
 
-NOMAD NORTH plugin for Visualization for Electronic Structural Analysis (VESTA)
+NOMAD NORTH plugin for Visualization for Electronic Structural Analysis (VESTA).
+
+# Explanation
+
+`nomad-north-vesta` is a GUI-based NORTH tool offering [`VESTA`](https://jp-minerals.org/vesta/en/) (software by [K. Momma and F. Izumi](https://doi.org/10.1107/S0021889811038970) for generating and visualizing crystal structures) for research on electron microscopy and
+crystal structure analysis.
 
 This `nomad` plugin was generated with `Cookiecutter` along with `@nomad`'s [`cookiecutter-nomad-plugin`](https://github.com/FAIRmat-NFDI/cookiecutter-nomad-plugin) template.