title: Sequelize how to use association table?
body: <p>I'm having an issue with Sequelize because I don't know how to approach the problem.</p>
  
  <p>I have 3 tables : A (game), B(platform) and AB (game_platform).
  A can have 1 to many B and B can have 0 to many A.
  To do that I made an association table : AB.</p>
  
  <p>In Sequelize I created the A,B,AB models then I did :</p>
  
  <pre><code>db.Game.belongsToMany(db.Platform, {as: 'Game', through: 'GamePlatformsJoin', foreignKey: 'game_platforms_fk_game'});
  db.Platform.belongsToMany(db.Game, {as: 'Platform', through: 'GamePlatformsJoin', foreignKey: 'game_platforms_fk_platform'});
  </code></pre>
  
  <p>Now this is how it will go :
  On my website platforms will be created and then games. When a game is created the user will need to define the platform(s) associated to it.
  But how can I tell Sequelize that I want a new entry in my association table ?
  I can add it as with any other table but is there a simpler way ?</p>