Label permission errors, and too many ids for /stale.

src/routes/users/fetch_user.rs

@@ -13,7 +13,7 @@ pub async fn req(user: User, target: Ref) -> Result<JsonValue> {
         .await?;
 
     if !perm.get_access() {
-        Err(Error::LabelMe)?
+        Err(Error::MissingPermission)?
     }
 
     Ok(json!(target.from(&user).with(perm)))

src/routes/users/find_mutual.rs

@@ -12,8 +12,8 @@ pub async fn req(user: User, target: Ref) -> Result<JsonValue> {
         .find(
             doc! {
                 "$and": [
-                    { "relations.id": &user.id },
-                    { "relations.id": &target.id }
+                    { "relations._id": &user.id },
+                    { "relations._id": &target.id }
                 ]
             },
             FindOptions::builder().projection(doc! { "_id": 1 }).build(),