I need to add another module to the site we just did. I need a place for people to enter tips for the delivery drivers. They should be able to leave a percentage or a dollar amount and whatever the tip is it needs to be added to the total before payment. So for instance, if someone leaves a 10% tip on a $12.74 order, $1.27 needs to be added to the total for the order. If they left a $2.00 tip on the same order the total would need to be $14.74. I have attached an image and highlighted the section that needs to be added in pink. Please let me know how quickly you can get it done and what it will cost.