title: accepts_nested_attributes_for with find_or_create?
body: <p>I'm using Rails' accepts_nested_attributes_for method with great success, but how can I have it <em>not</em> create new records if a record already exists?</p>
  
  <p>By way of example:</p>
  
  <p>Say I've got three models, Team, Membership, and Player, and each team has_many players through memberships, and players can belong to many teams.  The Team model might then accept nested attributes for players, but that means that each player submitted through the combined team+player(s) form will be created as a new player record.</p>
  
  <p>How should I go about doing things if I want to only create a new player record this way if there isn't already a player with the same name?  If there <em>is</em> a player with the same name, no new player records should be created, but instead the correct player should be found and associated with the new team record.</p>