add clean function

.vscode/settings.json

@@ -2,6 +2,7 @@
     "files.associations": {
         "*.ejs": "html",
         "ncurses.h": "c",
-        "stdio.h": "c"
+        "stdio.h": "c",
+        "string.h": "c"
     }
 }

Makefile

@@ -1,4 +1,6 @@
-build:
+clean:
 	rm -rf bin
+
+build:
 	mkdir -p bin
 	gcc -o bin/main *.c -lncurses