provided example of joining 3 or more streams in a tickscript, resolves #1290
provided example of joining 3 or more streams in a tickscript, resolves #1290

influxdata/docs.influxdata.com,influxdata/docs.influxdata.com,influxdata/docs.influxdata.com,influxdb/docs.influxdata.com,influxdata/docs.influxdata.com,influxdata/docs.influxdata.com,influxdb/docs.influxdata.com,influxdb/docs.influxdata.com