How to add users to vboxusers to enable USB usage

I want to use my flashdrive in Windows XP, which I am currently running in Virtualbox, but when I open up the settings to enable usb usage, I get an error:

Failed to access the USB subsystem.
VirtualBox is not currently allowed to access USB devices. 
You can change this by adding your user to the 'vboxusers' group. 
Please see the user manual for a more detailed explanation


Result Code: 
NS_ERROR_FAILURE (0x00004005)
Component: 
Host
Interface: 
IHost {30678943-32df-4830-b413-931b25ac86a0}
Callee: 
IMachine {22781af3-1c96-4126-9edf-67a020e0e858}

Does anyone know how to fix this!?

In your host, run this command:

sudo usermod -a -G vboxusers $USER

Now perform a logout (always required after add current user to a group).

After login, check that you are in the vboxusers group with this command, make sure that vboxusers is in the shown list:

groups $USER

This works for me and my problem with VirtualBox was solved

sudo usermod -a -G vboxsf "$USER"

1. Add the user as suggested by other answer using usermod command.
2. Run the command id. You should see vboxusers in the list.
3. If you don't see that, you may restart your computer and try id again.

When you get vboxusers listed as a result of running id, you're good to use USB with virtual box.

1. In a terminal run:

   sudo adduser $USER vboxusers
   

2. Reboot all systems.