Posts direct message from user's Twitter account
post_message(text, user, media = NULL, token = NULL)
Character, text of message.
Character vector of screen names or user ids.
See as_screenname()
for more details.
File path to image or video media to be included in tweet.
Use this to override authentication for
a single API call. In many cases you are better off changing the
default for all calls. See auth_as()
for details.