Federate user deletion (#551)

* Federate user deletion

- When someone deletes their account
- When a local user is banned

Fixes #509

* cargo fmt

plume-models/src/inbox.rs

@@ -53,6 +53,7 @@ pub fn inbox(ctx: &PlumeRocket, act: serde_json::Value) -> Result<InboxResult, E
         .with::<User, Create, Post>()
         .with::<User, Delete, Comment>()
         .with::<User, Delete, Post>()
+        .with::<User, Delete, User>()
         .with::<User, Follow, User>()
         .with::<User, Like, Post>()
         .with::<User, Undo, Reshare>()
@@ -286,6 +287,34 @@ pub(crate) mod tests {
         });
     }
 
+    #[test]
+    fn delete_user() {
+        let r = rockets();
+        let conn = &*r.conn;
+        conn.test_transaction::<_, (), _>(|| {
+            let (_, users, _) = fill_database(&r);
+
+            let fail_act = json!({
+                "id": "https://plu.me/@/Admin#delete",
+                "actor": users[1].ap_url, // Not the same account
+                "object": users[0].ap_url,
+                "type": "Delete",
+            });
+            assert!(super::inbox(&r, fail_act).is_err());
+
+            let ok_act = json!({
+                "id": "https://plu.me/@/Admin#delete",
+                "actor": users[0].ap_url,
+                "object": users[0].ap_url,
+                "type": "Delete",
+            });
+            assert!(super::inbox(&r, ok_act).is_ok());
+            assert!(crate::users::User::get(conn, users[0].id).is_err());
+
+            Ok(())
+        });
+    }
+
     #[test]
     fn follow() {
         let r = rockets();