I was offered a much better job position at another company and I accepted it. This doesn't imply a problem per se, but my current company is rather small and another worker, who was on the same team as me, left his position this week.
This situation would leave the company and the projects we work on with serious delays as my boss will have to try to replace our positions. How do I tell him that I'm planning to leave when my co-worker has also left recently? According to my contract, I am allowed to leave in 15 days.
EDIT: Thank you for your answers. I know that I have the right to quit if I notify on time. As @PagMax said, my question is about how to do that in a friendly manner, but I have a few more ideas now after reading your answers.