mmodify readme, check arguments

README.md

@@ -138,6 +138,18 @@ Make sure that you're capable of using the following development tools:
 - We'll announce **all** assignments before the semester begins.
 - Submit your solution to <https://gg.kaist.ac.kr/course/17>.
 - Read the documentation at <https://cp.kaist.ac.kr/cs220/cs220/>.
+- We provide grading scripts for each assignment. Before submission, you can check your grade with your machine.
+  - Grading scripts are located at `scripts/` directory.
+  - You can run the grading script with the following command:
+  ```bash
+  $ `scripts/grade.sh <assignment number>`
+  ```
+    - For example,
+    - If you want to grade `assignment9`, run the following command:
+      ```bash
+      $ cd scripts
+      $ ./grade.sh 9
+      ```
 - You're **allowed** to use ChatGPT or other LLMs. Instead, you'll solve more problems than previous semesters.