admin benutzer wird intial angelegt

backend/internal/db/users.go

@@ -2,6 +2,7 @@ package db
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/jackc/pgx/v5/pgxpool"
 
@@ -16,6 +17,26 @@ func NewUserStore(pool *pgxpool.Pool) *UserStore {
 	return &UserStore{pool: pool}
 }
 
+// SeedAdminUser creates an admin user if no users exist yet.
+// Returns (true, nil) if the user was created, (false, nil) if users already exist.
+func SeedAdminUser(ctx context.Context, pool *pgxpool.Pool, username, passwordHash string) (bool, error) {
+	var count int
+	if err := pool.QueryRow(ctx, `SELECT COUNT(*) FROM users`).Scan(&count); err != nil {
+		return false, fmt.Errorf("count users: %w", err)
+	}
+	if count > 0 {
+		return false, nil
+	}
+	_, err := pool.Exec(ctx,
+		`INSERT INTO users (username, password_hash, is_admin) VALUES ($1, $2, true)`,
+		username, passwordHash,
+	)
+	if err != nil {
+		return false, fmt.Errorf("insert admin: %w", err)
+	}
+	return true, nil
+}
+
 // ListUsers returns all users ordered by created_at.
 func (s *UserStore) ListUsers(ctx context.Context) ([]domain.User, error) {
 	rows, err := s.pool.Query(ctx,