Added docker-machine eval comment and IP note

tutorial.md

@@ -209,7 +209,7 @@ In this case, the client didn't tell the Docker Engine to publish any of the por
 
 Before we look at the **detached** mode, we should first find out a way to stop the container that you have just launched.
 
-First up, launch another terminal (command window) and execute the following command:
+First up, launch another terminal (command window) and execute the following command. If you're using docker-machine you need to run `eval $(docker-machine env <YOUR_DOCKER_MACHINE_NAME>)` in each new terminal otherwise you'll get the error "Cannot connect to the Docker daemon. Is the docker daemon running on this host?".
 ```
 $ docker ps
 CONTAINER ID        IMAGE                  COMMAND                  CREATED             STATUS              PORTS               NAMES
@@ -241,7 +241,7 @@ $ docker port static-site
 80/tcp -> 0.0.0.0:32773
 ```
 
-If you're on Linux, you can open [http://localhost:32773](http://localhost:32773) in your browser. If you're on Windows or a Mac, you need to find the IP of the hostname.
+If you're on Linux, you can open [http://localhost:32773](http://localhost:32773) (replace 32773 with your port for 80/tcp) in your browser. If you're on Windows or a Mac, you need to find the IP of the hostname.
 
 ```
 $ docker-machine ip default