Assign categories to expenses (#28)

* add expense categories

* set category to Payment for reimbursements

* Insert categories as part of the migration

* Display category groups

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Co-authored-by: Sebastien Castiel <sebastien@castiel.me>

src/lib/schemas.ts

@@ -45,6 +45,7 @@ export const expenseFormSchema = z
     title: z
       .string({ required_error: 'Please enter a title.' })
       .min(2, 'Enter at least two characters.'),
+    category: z.coerce.number().default(0),
     amount: z
       .union(
         [