Implement if condition to check propr function.

Author: russom

implement-and-rewrite-tests/implement/2-is-proper-fraction.js

@@ -15,4 +15,10 @@
 
 export function isProperFraction(numerator, denominator) {
   // TODO: Implement this function
+  if (numerator < denominator) {
+    return true;
+  } else {
+    return false;
+  }
 }
+