This relish goes well with grilled or roasted pork and steak, or cheese.
In a medium saucepan, bring vinegar, sugar, and 1/4 cup water to a simmer; stir until sugar has dissolved. Add remaining ingredients, bring to a rapid simmer, and cook until tomatoes are just tender and liquid has almost evaporated, about 14 minutes.
To store, refrigerate, up to 2 weeks.