I have these too. They are actually fungus gnats and are attracted to produce or house plant dirt. They have nested in my drains too. I have taken a plastic peanut butter jar and drilled a hole in the lid the size of a straw and inserted a short piece of the straw so it was even with the top of the lid and the bottom was about 1/4 to 1/3 down in the inside of the jar. I then have put small pieces of old fruit in the jar and I think you could use the vinegar solution so it in in the very bottom of the jar but a good distance from the bottom of the straw. The Gnats will go down the straw to get to the goodies and not be able to get back out. My daughter also used a banana skin in a plastic bag and leaving it in the sink overnight and the gnats go in and then in the morning close the bag quickly and take it outside and if you want keep it closed in some way and put it in the sun. Cooked gnats.
They can be a pest. I had a swarm in a bag of potting soil that I opened in doors.