Logging too much with SBT plugin

I’m trying to run gatling using the SBT plugin, which works fine, but I need to adjust how much stuff is being logged to the console. Specifically, it’s printing out every single HTTP request and response. I see nothing in the documentation at http://gatling.io/docs/2.1.7/extensions/sbt_plugin.html that says where to edit a config file (the solution I’ve seen pointed to for other similar things) for running things from the SBT plugin. Can someone tell me how to change this setting?

Logback is probably set to trace level and appending to the console. Try this: https://github.com/bbc/gatling-load-tests/blob/master/src/test/resources/logback-test.xml

Or your logback.xml file is simply missing.

It is missing - where should I put that file in the SBT project structure for it to be picked up?