add log on exited error code

app/coffee/DockerRunner.coffee

@@ -107,6 +107,7 @@ module.exports = DockerRunner =
 				if exitCode is 1 # exit status from chktex
 					err = DockerRunner.ERR_EXITED
 					err.code = exitCode
+					logger.err err:err, exitCode:exitCode, options:options, "docker container has exited"
 					return callback(err)
 				containerReturned = true
 				callbackIfFinished()