add explanation about how to use this file

main.py

@@ -43,6 +43,13 @@ def skipmap(self,text:str) -> list[int]:
         pass
 
 if __name__ == "__main__":
+    """
+    before running this file you need to compile c file and create dynamic linked library.
+    Please run following command.
+    ```bash
+    make lib
+    ```
+    """
     ft = C_ft("./pkg/ft_kmp_strstr.so")
 
     text="abababbabcabbaaaaaa"