设等比数列\(\{a_{n}\}\)的通项公式为\(a_{n}=q^{n-1}(n∈N^{*})\)，前\(n\)项和为\(S_{n}.\)若\(\lim\limits_{n→∞} \dfrac{{S}_{n}}{{a}_{n+1}} = \dfrac {1}{2}\)，则\(q=\) ______ ．