controllers::site_metadata: Use json! macro to simplify JSON serialization code

Author: Turbo87

src/controllers/site_metadata.rs

@@ -8,13 +8,8 @@ pub fn show_deployed_sha(req: &mut dyn RequestExt) -> EndpointResult {
     let deployed_sha =
         dotenv::var("HEROKU_SLUG_COMMIT").unwrap_or_else(|_| String::from("unknown"));
 
-    #[derive(Serialize)]
-    struct R<'a> {
-        deployed_sha: &'a str,
-        commit: &'a str,
-    }
-    Ok(req.json(&R {
-        deployed_sha: &deployed_sha[..],
-        commit: &deployed_sha[..],
-    }))
+    Ok(req.json(&json!({
+        "deployed_sha": &deployed_sha[..],
+        "commit": &deployed_sha[..],
+    })))
 }