add link to VNL-ATK package

user-doc/Introduction.md

@@ -36,6 +36,8 @@ As far as we know, the following MD codes can be used with PLUMED out of the box
 - [AceMD](http://www.multiscalelab.org/acemd/), see [this link](https://github.com/tonigi/ACEMD-PLUMED).
 - [OpenMM](http://openmm.org), using the [openmmp-plumed plugin](http://github.com/peastman/openmm-plumed).
 - [DL_POLY4](http://www.scd.stfc.ac.uk//research/app/ccg/software/DL_POLY/44516.aspx).
+- [VNL-ATK](https://quantumwise.com), see [this link](https://docs.quantumwise.com/tutorials/metadynamics_with_plumed/metadynamics_with_plumed.html).
+
 
 Please refer to the documentation of the MD code to know how to use it with the latest PLUMED release.
 If you maintain another MD code that is PLUMED-ready let us know and we will add it to this list.