Improve README

README.md

@@ -36,8 +36,11 @@ sc = SparkContext(conf=conf)
 spark = SparkSession(sc)
 
 etl.init_spark_session(spark, sc)
-etl.extraction(measurements=[var["name"]], \
+
+# This will extract the list of given variables and send the data to the specified INFLUXDB instance
+# Variable names become Influxdb metrics
+etl.extraction(measurements=["VARIABLE_1","VARIABLE_2"], \
                start_date='2020-07-12 00:00:00.000', \
                end_date='2020-07-12 04:00:00.000')
 
-```
\ No newline at end of file
+```