changed the var in the readme from code to params to be more clear
changed the var in the readme from code to params to be more clear

gavinballard/shopify_python_api,ifnull/shopify_python_api,asiviero/shopify_python_api,SmileyJames/shopify_python_api,varesa/shopify_python_api,Shopify/shopify_python_api,metric-collective/shopify_python_api