change the code in 'main.rb' in order to run a sample from scratch

the following aspects must be of public knowledge:
. i added the 'reports' folder to source control because it is not amusing to create such folder when i clone the .git repository from anywhere.
. the sample in 'main.rb' asumes that the 'db' and 'tables' already exists because this is the case in real life.
. the example follow the following steps:
	. fetch new data from the 'infosel' datasource and insert to db
	. fetch new data from the 'yahoo finance' datasource and insert to db
	. query database to generate reports