Updated add customer to use insert from customer_table
Changed to SQLAlchemy models for customer
Added pagination to show_customers view and template
Used Customer class in display_customer
Used Customer class in add_customer
Used Customer class in generate_premium
Removed customers_table
Add Premiums class
Used premiums class in display_customer_premiums
Used Premium class in generate_premium view
Added CustomerDemand class
Used CustomerDemand class in display_customer