Add missing Packages index file

Author: JJWTimmer

pom.xml

@@ -196,6 +196,7 @@
                                 <src>${project.basedir}/courses/GettingStarted</src>
                                 <src>${project.basedir}/courses/Rascalopedia</src>
                                 <src>${project.basedir}/courses/Bibliography</src>
+                                <src>${project.basedir}/courses/Packages</src>
                             </srcs>
                             <ignores>
                                 <ignore>|lib://rascal/org/rascalmpl/library/lang/rascal|</ignore>