Added JavaScript solution to issue wzhouwzhou#323

Author: jagw1re

javascript/remove_duplicates.js

@@ -0,0 +1,5 @@
+// Define array for duplicates to be removed
+const array = [2, 5, 2, 6, 8];
+// Create set from array (only adds non-duplicates) and print
+const unique = Array.from(new Set(array));
+console.log(unique);