slack v0.1.1 Slack.Plug.VerifyToken
Checks conn.private.slack_data
for :token
and compares it to
:token in the second function arguement list.
conn
is returned, unchanged, if the tokens are a match.
If the slack data token does not match the argument token, the
connection is halted and conn.status
is set to 400.
An error is raised if token argument is nil
.