Add a member to a list. The authenticated user must own the list to be able to add members to it. Note that lists cannot have more than 5,000 members.
|list_id||required||The numerical id of the list.|
|slug||required||You can identify a list by its slug instead of its numerical id. If you decide to do so, note that you'll also have to specify the list owner using the owner_id or owner_screen_name parameters.|
|user_id||required||The ID of the user for whom to return results. Helpful for disambiguating when a valid user ID is also a valid screen name.|
|screen_name||required||The screen name of the user for whom to return results. Helpful for disambiguating when a valid screen name is also a user ID.|
|owner_screen_name||optional||The screen name of the user who owns the list being requested by a slug.|
|owner_id||optional||The user ID of the user who owns the list being requested by a slug.|