added method to format sale amount properly
modified sales view to use formatted_sale_amount instead of sale_amount
added @sales instance variable to allow employee's sales to be displayed in the view
sales 'show' view now displays table of all employee's sales, sorted by descending amount
added link on employee emails that opens default email client
modified header on employee profile (show action). ALL CORE USER STORIES COMPLETE
Merge branch 'working'

Added small change to employees show.index.html.erb
Added links to views
Added link from sales#show back to sales#index
Added sales#new & create actions, sales_params method
Added sales#new and create routes
Added name method to Employee model
Added validations & invoice_frequencies method to Sale model
Added fields to new sale form
Deleted unnecessary create_sales files

I created a separate controller, views, etc. for “create sales” but
these functions actually belonged in sales_controller & views.
Added validations for invoice_no
Merge with working branch
Sales now ordered by descending sale date