For announcing post, I am using chat.postMessage which will basically, post Message from the logged in user when the post is published, but in that case, if a user wants to schedule any post, and then user logged out from RC, we will have a problem, in announcing the article, as Ghost is using access_token and user_id for announcing articles.
So the solution of the above problem is to implement webhook for Ghost and RC, and using that webhook the published post will be announced. So don't have to use access_token for postMessage, just create the message using the webhook token.
For announcing post, I am using chat.postMessage which will basically, post Message from the logged in user when the post is published, but in that case, if a user wants to schedule any post, and then user logged out from RC, we will have a problem, in announcing the article, as Ghost is using access_token and user_id for announcing articles. So the solution of the above problem is to implement webhook for Ghost and RC, and using that webhook the published post will be announced. So don't have to use access_token for postMessage, just create the message using the webhook token.