public static function signIn($username , $password)
	{
		$ip = self::getClientIp();
		$ua = ( isset( $_SERVER['HTTP_USER_AGENT'] ) ) ? $_SERVER['HTTP_USER_AGENT'] : '';
		$ts = date("U");

		if ( self::isValidPassword($username , $password) ) {

			self::sessionWrite( array( 'username' => $username ) );
			self::reload();
			self::$auth['users'][ $username ]['logincount'] = (int) @self::$auth['users'][ $username ]['logincount'] + 1;
			self::$auth['users'][ $username ]['lastlogin'] = array(
				'ip' => $ip,
				'ua' => $ua,
				'ts' => $ts
			);
			self::log( 'signin' , $username , $ts , $ip , $ua );
			self::save();

			return self::$auth['users'][ $username ];
		}

		self::log( 'signinerr' , $username , $ts , $ip , $ua );
		self::save();

		return false;
	}