Hello,
I am part of a university lab focused on open source software. We love Drawdb, and we want to offer it as a service in our university for professors teaching database modeling.

We are working with a professor in our university, and he has requested a few notation capabilities from our service. For example, he wants:

• Crow's-foot notation for the 'many' side of a relationship. I have opened PR #(lo que sea) to propose this as an optional feature.

Other requests:

• A notation with minimum and maximum matches
• A notation to mark whenever a FK is also the PK in the receiving table with a dotted line.
  Here are images of what we'd like to add: