Add node to Rust example

node-to-rust/src/lib.rs

@@ -0,0 +1,4 @@
+#[no_mangle]
+pub extern fn double_input(input: i32) -> i32 {
+    input * 2
+}

node-to-rust/src/main.js

@@ -0,0 +1,9 @@
+var ffi = require('ffi');
+
+var lib = ffi.Library('target/libdouble_input.so', {
+  'double_input': [ 'int', [ 'int' ] ]
+});
+
+var input = 4;
+var output = lib.double_input(input);
+console.log(input + " * 2 = " + output);