The connection lies in the shift from the ideals of the Bolshevik Revolution (as depicted in the early stages of the Soviet Union) to the authoritarian rule under Stalin. Just as in Animal Farm where the pigs take control and betray the original ideals of the rebellion, Stalin's regime deviated from the initial aspirations of the Bolsheviks.rephrase as a 9th grader

The connection is that both in Animal Farm and in the Soviet Union, there was a change from the initial goals of the revolution to a more authoritarian rule. In Animal Farm, the pigs take over and go against the original ideals of the rebellion, just like Stalin did in the Soviet Union.