problems: Add HasUploadedSolutionFilter for UserSolution
problems: Add HasUploadedSolutionFilter for UserSolution

tbabej/roots,rtrembecky/roots,matus-stehlik/roots,matus-stehlik/roots,matus-stehlik/roots,rtrembecky/roots,tbabej/roots,tbabej/roots,rtrembecky/roots