code: @Override
  	public String[] getUsersInRole(String role) {
  		if (role_list.containsKey(role)) {
  			return role_list.get(role).toArray(new String[0]);
  		} else {
  			return new String[0];
  		}
  	}
docs: Returns a list of users who have a particular role.
  
  @param role
  The role to search for.
  @return An array of usernames (String) that have that role.