CHANGELOG.md in benchmark_driver-0.15.15 vs CHANGELOG.md in benchmark_driver-0.15.16

@@ -1,4 +1,9 @@
+# v0.15.16
+
+- Add `--alternate` runner option to run executables alternately.
+  This is supported only for `ruby_stdout` runner for now.
+
 # v0.15.15
 
 - An absolute path is passed to `command_stdout`'s `working_directory`
   and v0.15.14's relative path resolution of job type