In \(\triangle ABC\), there is a right angle at \(B\) and the length of \(BC\) is twice the length of \(AB\). In other words, \(BC=2AB\).
Square \(DEFB\) is drawn inside \(\triangle ABC\) so that vertex \(D\) is somewhere on \(AB\) between \(A\) and \(B\), vertex \(E\) is somewhere on \(AC\) between \(A\) and \(C\), vertex \(F\) is somewhere on \(BC\) between \(B\) and \(C\), and the final vertex is at \(B\).
Square \(DEFB\) is called an inscribed square. Determine the ratio of the area of the inscribed square \(DEFB\) to the area of \(\triangle ABC\).