Update CONTRIBUTORS
Add cnsun@ to the list.
Closes
MOS_MIGRATED_REVID=150088886
@@ -82,6 +82,7 @@ John Shimek <varikin@gmail.com>
Brian Silverman <bsilver16384@gmail.com>
Michael Staib <mstaib@google.com>
John Sullivan <john.t.sullivan@gmail.com>
+Chengnian Sun <cnsun@google.com>
Keefer Taylor <keefer@google.com>
Michael Thvedt <mthvedt@google.com>
Cristopher Olson <topher.the.geek@gmail.com>
