add hex.pm info to app.src

src/gproc.app.src

@@ -9,6 +9,10 @@
   {id, "GPROC"},
   {registered, [ ] },
   {applications, [ kernel, stdlib ] },
-  {mod, {gproc_app, []} }
+  {mod, {gproc_app, []} },
+
+  {maintainers, ["Ulf Wiger"]},
+  {licenses, ["EPL"]},
+  {links, [{"Github", "https://github.com/uwiger/gproc"}]}
  ]
 }.