addFileToUser :: PushUData -> ApiResponse InternalUser
addFileToUser (Just user, file)
    | file `elem` iUserFiles user = failure FileExists
    | otherwise = success $ user { iUserFiles = file : iUserFiles user }
addFileToUser :: PushUData -> ApiResponse InternalUser
addFileToUser (Just user, file)
    | file `elem` iUserFiles user = failure FileExists
    | otherwise = success $ user { iUserFiles = file : iUserFiles user }
addFileToUser (Just user, file)
    | file `elem` iUserFiles user = failure FileExists
    | otherwise = success $ user { iUserFiles = file : iUserFiles user }