Consumers who allege the label of Skinnygirl Margarita is misleading may not join together to pursue their claims against the makers and promoters of the pre-mixed alcoholic beverage, a federal judge has ruled. In a written opinion Thursday, U.S. District Judge Manish S. Shah declined to certify a class of plaintiffs in a lawsuit filed by Amy Langendorf. The named plaintiff in a proposed class action must demonstrate that “the proposed class is sufficiently definite,” Shah wrote. A proposed class is …