Re-implement user relationships.

src/routes/users/fetch_relationships.rs

@@ -0,0 +1,14 @@
+use crate::database::entities::User;
+use rocket_contrib::json::JsonValue;
+use crate::util::result::Result;
+
+#[get("/relationships")]
+pub async fn req(user: User) -> Result<JsonValue> {
+    Ok(
+        if let Some(vec) = user.relations {
+            json!(vec)
+        } else {
+            json!([])
+        }
+    )
+}