Correct the description of --group-add in run.md
@@ -1056,7 +1056,7 @@ Both flags take limits in the `<device-path>:<limit>` format. Both read and
write rates must be a positive integer.
## Additional groups
- --group-add: Add Linux capabilities
+ --group-add: Add additional groups to run as
By default, the docker container process runs with the supplementary groups looked
up for the specified user. If one wants to add more to that list of groups, then
