Moved from sqlContext to spark in chapter 8
Moved from sqlContext to spark in chapter 8

naoyak/Agile_Data_Code_2,naoyak/Agile_Data_Code_2,rjurney/Agile_Data_Code_2,naoyak/Agile_Data_Code_2,rjurney/Agile_Data_Code_2,rjurney/Agile_Data_Code_2,rjurney/Agile_Data_Code_2,naoyak/Agile_Data_Code_2