Add tax_percentage column to invoices table. Mock views on edit invoice page.
Create update tax_percentage form.
Rename column from tax_percent to sales_tax.
Hide error message that does not apply on edit invoice form.
Convert invoice sales_tax integer into decimal. (7sales_tax * 0.01 = 0.07sales_tax!).
Remove sales_tax presence and numericality validations. Create before_validation that changes a blank sales_tax item into a 0.
Update quarterly and yearly total less taxes methods to use invoice sales tax.
Round(2) service sales tax. Prevent working with numbers 3rd decimal to the right.
Prevent sales_tax from being a negative number.
Prevent invoices from being edited or deleted if any payments are applied.
Up EasyKeep version to 1.3.0