1) added tips for fixing learning rate alpha 2) steps for doing polynomial regression
1) added tips for fixing learning rate alpha 2) steps for doing polynomial regression

dastearns/machineLearning,hodachop93/machineLearning,M4573R/machineLearning-3,JizhiziLi/machineLearning,nempau/machineLearning,quinnliu/machineLearning