Hi, Glad to apply to your offer.
I have gone through your job description in depth, and now I am sure that I can develop what you want exactly to your expectations, OR more.
I have been through many frameworks that boosts effectiveness, performance and security of the whole system. So I will select the most suitable framework for this job if you don't mind.
Responsiveness of the website can be guaranteed with my skills in up-to-dated PHP technology and other 3rd-party libraries like Twitter-bootstrap.
And I am -Well versed in RDBMs such as Oracle and MySQL.
Option for the database totally depends on your preference if you have any, 'cause I can make use of almost all the popular DBs (mySQL, MongoDB, Neo4j, Oracle, etc...)
As an Ethical Hacker, I always include Security breach scenarios in QA testing(i.e. SQL Injection) so that no black-hat guy could make compromise on your website.
Deadline will be definitely met, updates will be swift, communication will be more than smooth, not to mention the Topmost quality that I guarantee.
I will look forward to hearing from you.