Things Done:
(1) Adding new Gem: will_paginate, roo.
(2) Make supplier on Purchase form, and product on Purchase Detail form being advanced.
(3) Added [Close] and [Void] button on Purchase and Sale.
(4) Preparing for import from excel feature.

Next to-do:
(1) Get price for Sale Detail.
(2) Finish import feature for Supplier, Supplier Phone, Supplier Categories, Customer, Customer Phone, Product.
(3) Take purchase price product purchase.
(4) Search Price feature.