Set the docker image correctly when a server is updated; closes pterodactyl/panel#2356

environment/docker/environment.go

@@ -176,3 +176,9 @@ func (e *Environment) SetStopConfiguration(c *api.ProcessStopConfiguration) {
 	e.meta.Stop = c
 	e.mu.Unlock()
 }
+
+func (e *Environment) SetImage(i string) {
+	e.mu.Lock()
+	e.meta.Image = i
+	e.mu.Unlock()
+}

server/server.go

@@ -137,6 +137,7 @@ func (s *Server) SyncWithConfiguration(cfg *api.ServerConfigurationResponse) err
 	// the process isn't just terminated when a user requests it be stopped.
 	if e, ok := s.Environment.(*docker.Environment); ok {
 		s.Log().Debug("syncing stop configuration with configured docker environment")
+		e.SetImage(s.Config().Container.Image)
 		e.SetStopConfiguration(&cfg.ProcessConfiguration.Stop)
 	}