Update README.md

tutorials/README.md

@@ -3,17 +3,12 @@
 Here we provide tutorials that demonstrate usage of JGNN in domain-specific tasks.
 We do not delve into inner workings of the library,
 as these are mainly covered in the [Guidebook](https://mklab-iti.github.io/JGNN/).
-Below we summarize available material.
+Below we summarize available material. 
+Click on titles to move to corresponding documents.
 
 **This material is still incomplete.**
 
-
-<a href="trajectories.md" style="text-decoration: none;">
-  <button style="background-color: #0A5C36; color: white; padding: 10px 20px; margin-bottom:10px; margin-top:10px; border: none; border-radius: 5px; cursor: pointer;">
-    Trajectory classification
-  </button>
-</a>
-
+[![Link](https://img.shields.io/badge/Trajectory%20classification-0A5C36)](trajectories.md) <br>
 Some simulated trajectory measurements are obtained across time steps
 that are organized into line graphs. There are two types of trajectories:
 those with full data, and those for which parts of trajectory data are missing.