📝 Added sandbox (code sketchbook)

sandbox/hello.rs

@@ -0,0 +1,20 @@
+// this is a comment, and is ignored by the compiler
+//
+// this is the main fucntion
+/* this is a
+ * multiline comment*/
+
+fn main() {
+    // statements here are executed when the compiled binary is called
+    //
+    // print text to the console
+    println!("Hello World!");
+}
+
+// to compile simply enter into terminal:
+// rustc hello.rs
+// this will create a binary under the same name, simply run:
+// ./hello
+//
+// OUTPUTS:
+// Hello World!