error in db code, closing database before usage

Backend/database.go

@@ -5,10 +5,8 @@ import (
 	"arbeitszeitmessung/models"
 	"database/sql"
 	"fmt"
-	"log"
 
-	"github.com/golang-migrate/migrate/v4"
-	_ "github.com/golang-migrate/migrate/v4/source/file"
+	_ "github.com/lib/pq"
 )
 
 func OpenDatabase() (models.IDatabase, error) {
@@ -18,18 +16,5 @@ func OpenDatabase() (models.IDatabase, error) {
 	dbPassword := helper.GetEnv("POSTGRES_API_PASS", "password")
 
 	connStr := fmt.Sprintf("postgres://%s:%s@%s:5432/%s?sslmode=disable&TimeZone=Europe/Berlin", dbUser, dbPassword, dbHost, dbName)
-	db, err := sql.Open("postgres", connStr)
-	if err != nil {
-		return nil, err
-	}
-	defer db.Close()
-	return db, err
-}
-
-func MigrateDB(db models.IDatabase, connStr string) {
-	m, err := migrate.New("file:///../migrations/", connStr)
-	if err != nil {
-		log.Fatalln("Error starting migration", err)
-	}
-	m.Up()
+	return sql.Open("postgres", connStr)
 }