first stab on bill model

db/enums.ts

@@ -0,0 +1,23 @@
+export enum BOOKING_STATUS {
+  REQUESTED = 'requested',
+  CONFIRMED = 'confirmed',
+  REJECTED = 'rejected',
+  CANCELED = 'canceled',
+}
+
+export enum BILL_STATUS {
+  UNINVOICED = 'uninvoiced',
+  INVOICED = 'invoiced',
+  PAID = 'paid',
+}
+
+export enum MILAGE_RATES {
+  INTERN_UP_TO_200 = 0.37,
+  INTERN_200_100 = 0.22,
+  INTERN_1001_2000 = 0.15,
+  INTERN_OVER_2000 = 0.13,
+  EXTERN_UP_TO_200 = 0.42,
+  EXTERN_200_100 = 0.25,
+  EXTERN_1001_2000 = 0.2,
+  EXTERN_OVER_2000 = 0.18,
+}