Update chatops_on_gitlabcom.md to clarify process

- only someone who is already a member can add someone to chatops

doc/development/chatops_on_gitlabcom.md

@@ -14,7 +14,7 @@ tasks such as:
 To request access to Chatops on GitLab.com:
 
 1. Log into <https://ops.gitlab.net/users/sign_in> **using the same username** as for GitLab.com (you may have to rename it).
-1. Ask in the [#production](https://gitlab.slack.com/messages/production) channel to add you by running `/chatops run member add <username> gitlab-com/chatops --ops`.
+1. Ask in the [#production](https://gitlab.slack.com/messages/production) channel for an existing member to add you to the `chatops` project in Ops. They can do it by running `/chatops run member add <username> gitlab-com/chatops --ops` command in that channel.
 
 NOTE: **Note:** If you had to change your username for GitLab.com on the first step, make sure [to reflect this information](https://gitlab.com/gitlab-com/www-gitlab-com#adding-yourself-to-the-team-page) on [the team page](https://about.gitlab.com/company/team/).