Volume myapp_sync declared as external, but could not be found

[Tutt-J]

When I run "make install" I have this error :

Volume myapp_sync declared as external, but could not be found. Please create the volume manually using `docker volume create --name=myapp_sync` and try again.
Makefile:11: recipe for target 'install' failed
make: *** [install] Error 1

So i do the command manually, maybe a good idea to automatate this.