1. Add a comment table to db, generate the O/R mapping file and corresponding DAO, POJO java file.
2. Change the hibernate default dialect class to my custom one to fix the blob problem when query by sql.
3. Add a permisson define xml for the auth verify later.
4. Change list all article function to using sql that configure in XML rather than Hibernate HQL.

Signed-off-by: shadberry <shadberry89@gmail.com>