Add currency

prisma/migrations/20231206201409_add_currency/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Group" ADD COLUMN     "currency" TEXT NOT NULL DEFAULT '$';

prisma/schema.prisma

@@ -14,6 +14,7 @@ datasource db {
 model Group {
   id           String        @id
   name         String
+  currency     String        @default("$")
   participants Participant[]
   expenses     Expense[]
 }