init medoids

def initMedoids(self, X):
        ''' 
        Parameters
        ----------
        X: input data. 
        '''
        self.medoids = []
        
        #Starting medoids will be random members from data set X
        indexes = np.random.randint(0, len(X)-1,self.k)
        self.medoids = X[indexes]
        
        for i in range(0,self.k):
            self.medoids_cost.append(0)