more changes to the SQL creating script

@dovtu's changes were correct although partial, we have to completly split the "comments" table to 2 tables,
I split Comments table to: 1. Comments 2. rating, before I split it didnt make any sense at all,
for each comment there was ITS OWN RATING which ment that there can be 1+ diffrent ratings, all unconnected...
also added the 'alter table' command to add foreign key to the new table "Rating".