let the first controller work complete, means all crud opartions work fine for it
There are the following Entites as CRUD entities now:
EmailSubscriber
SubscriberGroup
Newsletter
all needed crud operations are working. The rel subscribers inside the groups are a little bit buggy but the groups inside of the subscriber are working cool.

Need to plan the dependencies for the newsletter itself:
articles (could be external things, too, need a interface for it)
files
groups
single emails
types, maybe as objects with specific send/render methods for simple text or rendered html content