Improve health check endpoint to test database connection

storage/storage.go

@@ -17,3 +17,20 @@ type Storage struct {
 func NewStorage(db *sql.DB) *Storage {
 	return &Storage{db}
 }
+
+// DatabaseVersion returns the version of the database which is in use.
+func (s *Storage) DatabaseVersion() string {
+	var dbVersion string
+	err := s.db.QueryRow(`SELECT current_setting('server_version')`).Scan(&dbVersion)
+	if err != nil {
+		return err.Error()
+	}
+
+	return dbVersion
+}
+
+// Ping checks if the database connection works.
+func (s *Storage) Ping() error {
+	_, err := s.db.Exec(`SELECT true`)
+	return err
+}