JSON output file has improved format

src/parser.rs

@@ -101,7 +101,7 @@ pub mod parser {
         pub fn save_file(&self, vals: Vec<SomeObject>) -> std::io::Result<()> {
             let filename: String = String::from("numbers.json");
 
-            let json = serde_json::to_string(&vals).unwrap();
+            let json = serde_json::to_string_pretty(&vals).unwrap();
             let mut file = File::create(filename)?;
             file.write_all(json.as_bytes())?;
             Ok(())