gistfile1.txt

var User = function () {
  this.hasMany('Messages');
  this.hasMany('ConversationMemberships');
  this.hasMany('Conversations', {through: 'ConversationMembership'});
};

var Conversation = function () {
  this.hasMany('Messages');
  this.hasMany('ConversationMemberships');
  this.hasMany('Users', {through: 'ConversationMembership'});
};

var ConversationMembership = function () {
  this.belongsTo('User');
  this.belongsTo('Conversation');
};

var Message = function () {
  this.belongsTo('User');
  this.belongsTo('Conversation');
};