public boolean userExists(String name) throws IOException{ //checks if member exists
      br = new BufferedReader(new FileReader("output.txt"));
      String line = br.readLine();
      while(line != null){
         String parts[] = line.split(" ");
         if(name.equals(parts[0])) {
            return true;
         }
         line = br.readLine();
      }
      return false;
   }