Added credentials file.

README.md

@@ -44,3 +44,15 @@ http://wiki.evilmadscientist.com/Installing_software
 				#		return serialPort
 		- In my version lines 1355-1360
  
+
+## Setup
+Add credentials.h file with content like this:
+
+    const char *kWifiSsid = "MySSID";
+    const char *kWifiPassword = "MySecret";
+
+To disable Wifi:
+
+    const char *kWifiSsid = 0;
+    const char *kWifiPassword = 0;
+