Can't run shopping app

[sb-snrg]

Hi Gabriel Volpe

First of all, thanks for your excellent book.
I can't run the shopping app. i'm on mac and I use docker for mac. Need your help, I'm newbie.

`Removing app_shopping_cart_1
Recreating a5556a84df46_app_shopping_cart_1 ... error

ERROR: for a5556a84df46_app_shopping_cart_1 Cannot start service shopping_cart: OCI runtime create failed: container_linux.go:380: starting container process caused: exec: "/opt/docker/bin/shopping-cart-core": stat /opt/docker/bin/shopping-cart-core: no such file or directory: unknown

ERROR: for shopping_cart Cannot start service shopping_cart: OCI runtime create failed: container_linux.go:380: starting container process caused: exec: "/opt/docker/bin/shopping-cart-core": stat /opt/docker/bin/shopping-cart-core: no such file or directory: unknown
ERROR: Encountered errors while bringing up the project.`

[gvolpe]

See #448, and for questions, please prefer the Gitter channel.