Online ordering

Question

I developed point-of-sale software for a pizza company in my region. They have ~100 locations. They are asking that I begin work on online ordering. I have plenty of time, so I do not with to outsource this. The software I developed uses sqlite as the database. Can anyone recommend a way to handle this to get me started in the right direction? I was thinking about maybe using something as simple as encoded emails, generated from a web form.