fixed backend test compilation

source/orm/sql/connection.cpp

@@ -45,6 +45,11 @@ connection &connection::operator=(const connection &x) {
   return *this;
 }
 
+connection::connection( connection&& x ) noexcept
+: connection_info_(std::move(x.connection_info_))
+, connection_(std::move(x.connection_))
+, logger_(std::move(x.logger_)) {}
+
 connection & connection::operator=(connection &&x) noexcept {
   connection_info_ = std::move(x.connection_info_);
   connection_  = std::move(x.connection_);