add web application to 'how to invite a new user' page

howto/matrix-invite-user.md

@@ -1,5 +1,17 @@
 ## inviting someone to matrix
 
+
+
+### using the web application
+
+https://cyberia.club/matrix-register
+
+You will need the registration_shared_secret string which is in the matrix server config file 
+
+`cat /etc/matrix-synapse/homeserver.yaml | grep 'registration_shared_secret'`
+
+### using the shell script
+
 When someone requests access to matrix they have to provide us with a username. you will enter that username in the command below:
 
 ```