def watchers(self, project):
        return self.get_values("show", project, "watchers", filter="watchers")
read table from infile and group.
dataset/ETHPy150Open ask/python-github2/github2/repositories.py/Repositories.watchers--crossover with--dataset/ETHPy150Open CGATOxford/cgat/scripts/table2table.py/readAndGroupTable