title: sequelize "findbyid" is not a function but apparently "findAll" is
body: <p>I am getting a very strange problem with sequelize, When I try to call the function findAll it works fine (same for create and destroy), but when I try to call function "findById", it throws "findById is not a function" (same for "FindOne").</p>
  
  <pre><code>//works fine
  var gammes = models.gamme.findAll().then(function(gammes) {
          res.render('admin/gammes/gestion_gamme',{
              layout: 'admin/layouts/structure' ,
              gammes : gammes,
              js: "gammes"
          });
      });
  
  // throws models.gamme.findById is not a function
  models.gamme.findById(req.params.id).then(function(gamme) {
          gamme.update({
              nom: req.body.nom
          }).then(function () {
              res.redirect("/gammes");
          })
      });
  </code></pre>
  
  <p>Gamme.js model</p>
  
  <pre><code>module.exports = function (sequelize, DataTypes) {
      "use strict";
      var gamme = sequelize.define('gamme', {
          id_gamme: {
              type: DataTypes.INTEGER.UNSIGNED,
              autoIncrement: true,
              primaryKey: true
          },
          nom: {
              type: DataTypes.STRING,
              allowNull: false
          }
      }, {
          classMethods: {},
          timestamps: false
      });
      return gamme;
  };
  </code></pre>