slack.comsave.slackr enables you upload R objects (as an R data file)
to slack.com and (optionally) post them to one or more channels
(if channels is not empty).save.slackr(..., channels = "", file = "slackr",
api_token = Sys.getenv("SLACK_API_TOKEN"))httr response object from POST callslackrSetup, dev.slackr, slackrUpload