When creating budget add expense classes from previous budget automatically

Purpose: Managing expense classes could be cumbersome if they need to be added manually whenever a budget is created.

Scenarios:

1. Scenario:
   • Given the current budget has one or more expense classes
   • When user OR system create a new budget for the coming year
   • Then all expense classes from the previous year are added automatically
   • AND they have the same status as they did in the previous year at time of budget creation