Add troubleshooting

manuscript/reference/troubleshooting.md

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+# Troubleshooting
+
+Having difficulty with a recipe? Here are some tips..
+
+## Why is my stack not launching?
+
+Run ```docker stack ps <stack name> --no-trunc``` for more details on why individual containers failed to launching
+
+## Attaching to running container
+
+Need to debug **why** your oauth2_proxy container can't talk to its upstream app? Start by identifying which node the proxy container is running on, using ```docker ps <stack name>```.
+
+SSH to the host node, and attach to the container using ```docker exec -it <continer id> /bin/bash``` (_substitute ```/bin/ash``` for ```/bin/bash```, in the case of an Alpine container_), and then try to telnet to your upstream host.
+
+## Watching logs of container
+
+Need to see what a particular container is doing? Run ```docker service logs -f <stack name>_<container name>``` to watch a particular service. As the service dies and is recreated, the logs will continue to be displayed.