Combine all ingredients in a jar and shake to incorporate. Sauce will keep in the refrigerator for a few days, or, while stir fry vegetables are cooking, heat sauce in a small saucepan on medium-high heat. Stir frequently, about 5 minutes, until sauce begins to simmer. Reduce heat to medium, sauce should begin to thicken. Cook for another 3 minutes, or until sauce is thick enough to coat the spoon. Keep warm until ready to toss with the stir fry.