Overview:    Abstract DAO
Module:      Backend
Description: Add get key count method to DAO
Overview:    Can query items for page
Module:      Backend
Description: Add 'where query' to AbstractDAO. Add query items for page to shop class. Add query by page route to 'main'
Overview:   Add title bar to page
Module:     Frontend
Description:Add title bar to page.
Overview:   Query less data once
Module:     Frontend
Description:Query the items in first page instead of all the data