avoid the rtm api when sending messages
avoid the rtm api when sending messages

it’s janky

closes https://github.com/looker/looker-slackbot/issues/54

PotomacInnovation/looker-slackbot,looker/lookerbot,looker/lookerbot,PotomacInnovation/looker-slackbot,jarlathp/lookerbot,jarlathp/lookerbot