Change maintainers (#2147)

changes maintainers to shows who is active on the project as of today.

MAINTAINERS

@@ -1,10 +1,22 @@
+Core maintainers
+================
+
 Benoit Chesneau <benoitc@gunicorn.org>
-Paul J. Davis <paul.joseph.davis@gmail.com>
-Randall Leeds <randall.leeds@gmail.com>
 Konstantin Kapustin <sirkonst@gmail.com>
+Randall Leeds <randall.leeds@gmail.com>
+Berker Peksağ <berker.peksag@gmail.com>
+Jason Madden <jason@nextthought.com>
+
+Alumni
+======
+
+This list contains maintainers that are no longer active on the project.
+It is thanks to these people that the project has become what it is today.
+Thank you!
+
+
+Paul J. Davis <paul.joseph.davis@gmail.com>
 Kenneth Reitz <me@kennethreitz.com>
 Nikolay Kim <fafhrd91@gmail.com>
 Andrew Svetlov <andrew.svetlov@gmail.com>
-Stéphane Wirtel <stephane@wirtel.be>
-Berker Peksağ <berker.peksag@gmail.com>
-Jason Madden <jason@nextthought.com>
+Stéphane Wirtel <stephane@wirtel.be>