Texting users don't use the FieldChat app, but may want to see who is in a channel or remove themselves from a channel. The user can send a text message with a * at the beginning, and instead of sending the message to everyone, it will be interpreted as a command.
*stop
Remove me from the current channel on this phone number so I no longer receive any text messages from it.
*list users
Show me a list of all the users in the channel for this phone number, along with their contact info.
*channel
Show the name of the channel for this phone number and the users in it.
