removed duplicates

AUTHORS

@@ -50,7 +50,6 @@ Valera Rozuvan <valera.rozuvan@gmail.com>
 Diana Huang <dkh@edx.org>
 Marco Morales <marcotuts@gmail.com>
 Christina Roberts <christina@edx.org>
-Valera Rozuvan <valera@edx.org>
 Robert Chirwa <robert@edx.org>
 Ed Zarecor <ed@edx.org>
 Deena Wang <thedeenawang@gmail.com>
@@ -72,4 +71,3 @@ Steve Strassmann <straz@edx.org>
 Giulio Gratta <giulio@giuliogratta.com>
 David Baumgold <david@davidbaumgold.com>
 Jason Bau <jbau@stanford.edu>
-Giulio Gratta <caesar2164@gmail.com>