add phanupongr.rs (#174)

Rust/phanupongr.rs

@@ -0,0 +1,15 @@
+use std::io;
+
+fn main() {
+    loop {
+        println!("Enter only `Coffee`: ");
+        let stdin = io::stdin();
+        let mut coffee = String::new();
+        stdin.read_line(&mut coffee).expect("Failed to read input.");
+
+        if coffee.contains("Coffee") {
+            println!("{}", coffee.replace("ffe", "d"));
+            break
+        }
+    }
+}