For what values $$k$$ is the following function continuous at $$x=-\dfrac{\pi}{6}$$ ?
$$f\left( x \right) = \left\{ \begin{array}{l}\dfrac{{\sqrt 3 \sin x + \cos x}}{{x + \dfrac{\pi }{6}}}\,,\,x \ne - \dfrac{\pi }{6}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,k\,\,\,\,\,\,\,\,\,\,\,\,\,\,,x = - \dfrac{\pi }{6}\end{array} \right.$$