Add primary key to FilesForMachinesTable

Introduce a primary key field 'id' with UUID type to the FilesForMachinesTable. This ensures each record is uniquely identifiable and improves database integrity. Additionally, set a default value to a random UUID for new entries.

apps/backend/src/app/db/schema.ts

@@ -153,6 +153,8 @@ export const MachinesTable = pgTable("machines", {
 
 //TODO Many to Many table betwen File en Machine
 export const FilesForMachinesTable = pgTable("files_for_machines", {
+	id: p.uuid('id').primaryKey().notNull().defaultRandom(),
+
 	fileId: p
 		.uuid("file_id")
 		.notNull()