That would explain it! So I guess the best solution is to manually drop the ignored_users table (after taking a backup). Then the migration should be able to run successfully.
@Shashikant_Sharma are you using a standard installation from our install guide? If so, please try running
cd /var/discourse
./launcher enter app
su -c 'psql discourse' postgres
Then run
SELECT version, name, created_at from schema_migration_details ORDER BY created_at DESC LIMIT 10;