Added new visiting PhD student to group

Author: amjjbonvin

_data/members.yml

@@ -92,6 +92,10 @@
   position: Visiting Ph.D Candidate
   avatar: /images/people/Cintia-Leal.png
 
+- name: Andrea Villani
+  position: Visiting Ph.D Candidate
+  avatar: /images/people/Andrea-Villani.png
+
 - name: Jahaciel Villaverde Nogues
   position: M.Sc Student
   avatar: /images/people/Jahaciel-Villaverde.jpg