Update Tweet Webhook

Fix #1
Fix #2

Signed-off-by: jolheiser <john.olheiser@gmail.com>

handler/twitter.go

@@ -52,7 +52,8 @@ func (t *Twitter) Tweet(tweet *twitter.Tweet) {
 	}
 
 	w := &disco.Webhook{
-		Username: tweet.User.Name,
+		Username:  "@" + tweet.User.ScreenName,
+		AvatarURL: tweet.User.ProfileImageURLHttps,
 		Content:   fmt.Sprintf("https://twitter.com/%d/status/%d", tweet.User.ID, tweet.ID),
 	}
 	if _, err := w.Send(context.Background(), t.Filter.Webhook); err != nil {