Creates IDs for both players/teams

def _create_ids(self, home_teams, away_teams):
        """
        Creates IDs for both players/teams
        """
        categories = pd.Categorical(np.append(home_teams,away_teams))
        home_id, away_id = categories.codes[0:int(len(categories)/2)], categories.codes[int(len(categories)/2):len(categories)+1]
        return home_id, away_id