Here "city gate" is associated with leadership of a town. Alternate translation: "The important people of the city" (See: [[rc://en/ta/man/jit/figs-metonymy]])
The writer speaks of himself as if he was the person about whom the drunkards sing mocking songs. Alternate translation: "the drunkards of the city sing disgusting songs about me" (See: [[rc://en/ta/man/jit/figs-metaphor]])