#18 Move where block is yielded at connection: a block was yielded at the connection open because we wanted messages to only be processed when the websocket was already open. All messages are sent via the API anyway, we just go through the RTMConnection object to get the user->channel mapping, which is already populated by rtm_start data and doesn't depend on the websockets connection being up.
#21 Creates users and rooms after connecting to the websocket: creation of rooms and users was happening before the websocket got connected and in a Slack org with thousands of users and rooms it was exceeding the 30s timeout on the websocket URL provided by Slack. This moves the user and room creation to happen only once we secured the websocket connection.