Slack DM to a user not in `im.list`
I'm implementing a slack ops bot that will notify users of job completion on a build server. It needs to be able to DM users on job completion. I've setup a bot user as per the instructions @ https://api.slack.com/bot-users . To send a DM to a particular user, chat.postMessage takes the first argument (channel) as either a @username or a IM channel's ID as per the documentation @ https://api.slack.com/methods/chat.postMessage#channels . To get the IM channel ID of a user, im.list can be used. But im.list only gives the IM channel IDs of the users the bot has previously interacted with (or the