title: How to let a user join channel in Slack App
body: <p>I am working on a slack app which has its bot also.A user can share a file from the bot to any public channel even if he is not in that channel. If user is not in the channel then firstly I will add the user in the channel and then share the file. For this slack provides api <a href="https://api.slack.com/methods/channels.join" rel="nofollow noreferrer">https://api.slack.com/methods/channels.join</a> which helps a user join a channel. But it expects a user token corresponding to the user who wants to join the channel. Now the issue is I only have bot token(xoxb-) and api token(xoxp-) corresponding to the user which has installed the app. So how can I get the token corresponding to any user whom I want to join OR I am missing something here. Please help.</p>