title: How design an entity to entity relation in my SQL database
body: <p>I have a problem with design an entity to entity relation in my SQL database.
  I have an entity that acts as a 'group'. And all groups has a relations to each other.</p>
  
  <p>As an example:
  GroupA and GroupB has a relation from groupA to groupB and vice versa with a bool.
  It is like a 2D matrix:</p>
  
  <p>Name | GroupA | Group B |</p>
  
  <p>Group A | true | false</p>
  
  <p>Group B | false | true |</p>
  
  <p>The groups are dynamic, may there are more or less groups.
  Now, how should I store this in my database?</p>
  
  <p>Sorry for my bad english, and I hope someone understand what I mean :)</p>