Add code for budgets

app/Repositories/Budget/BudgetRepositoryInterface.php

@@ -185,6 +185,16 @@ interface BudgetRepositoryInterface
      */
     public function setUser(User $user);
 
+    /**
+     * Used in the v2 API to calculate the amount of money spent in all active budgets.
+     *
+     * @param Carbon $start
+     * @param Carbon $end
+     *
+     * @return array
+     */
+    public function spentInPeriod(Carbon $start, Carbon $end): array;
+
     /**
      * @param array $data
      *