CONTRIBUTORS in activemerchant-1.20.4 vs CONTRIBUTORS in activemerchant-1.21.0

@@ -257,5 +257,18 @@
 * James Armstead (armsteadj1)
 
 Samurai (November, 2011)
 
 * Joshua Krall (jkrall)
+
+CertoDirect Gateway (February, 2012)
+
+* Aleksei Gusev (hron)
+
+Authorize.Net SIM Integration (February, 2012)
+
+* Roger Pack (rdp)
+* Nick Rogers (courtland)
+
+NAB Transact (AU) Gateway (February, 2012)
+
+* Tom Meier (tommeier)