Computed Field not showing
I think it must be a bug, since the computed module is in alpha for drupal 8 at the time of this writing. With the help of Matt, we were able to print a simple 'hello' message by manually creating a new node. This new node will have access to the new computed field. I was using the devel module to generate content for nodes, which for some reason did not have access to the computed field. So if you are experiencing the same problem, set up your computed field, and then manually create a node, or edit and resave a node your previously created manually. That worked for me.