Update README.md

Author: alesanchezr

exercises/04.1-Print-the-last-one/README.md

@@ -1,3 +1,7 @@
+---
+tutorial: https://www.youtube.com/watch?v=d-CnlwX6x1A
+---
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 # `04.1` Print the last one
 
 You will never know how many items `myStupidArray` has because it is being randomly generated during runtime using the `generateRandomArray` function.
@@ -11,4 +15,4 @@ var totalItems = myStupidArray.length;
 # 📝 Instructions
 
 1. Create a variable named theLastOne, and assign it the LAST element of myStupidArray. 
-2. Then, print it on the console.
+2. Then, print it on the console.