Make posts unlisted

src/main.rs

@@ -62,6 +62,7 @@ struct Token {
 #[derive(serde::Serialize)]
 struct Status {
     status: String,
+    visibility: &'static str,
 }
 
 impl Mastodon {
@@ -164,6 +165,7 @@ impl State {
         let res = self.client.post(url.as_str())
             .form(&Status {
                 status: name,
+                visibility: "unlisted",
             })
             .send()
                 .compat()