The equation of a curve is given by \(y = 2x^2 + kx + k - 1\), where \(k\) is a constant. Given that \(k = 2\), express the equation of the curve in the form \(y = 2(x + a)^2 + b\), where \(a\) and \(b\) are constants. Also, state the coordinates of the vertex of the curve.