title: Sequelize: Cannot filter childs table for a specific user
body: <p>I'm using nodejs v8.9.0 + expressjs v4.14.0 + sequelize v3.25.0 to build a web app in which people can ask questions each others and publish articles. </p>
  
  <p>I have these models:</p>
  
  <p>/** USER MODEL **/</p>
  
  <pre><code>module.exports = function(sequelize, DataTypes) {
  var User = sequelize.define('users', {
      firstName: {
          type: DataTypes.STRING(50),
          field: 'firstName' 
      },
      lastName: {
          type: DataTypes.STRING(200),
          field: 'lastName' 
      },
      email: {
          type: DataTypes.STRING(200),
          field: 'email'
      },
  },
  {
      classMethods: {
          User.belongsToMany(
              models.questions, 
              {
                  through: 'QuestionRecipient',  foreignKey: 'userId'
              }
          );
      }
  })
  </code></pre>
  
  <p>/** QUESTION MODEL **/</p>
  
  <pre><code>module.exports = function(sequelize, DataTypes) {
  var Question = sequelize.define('questions', {
      content: {
          type: DataTypes.TEXT,
          field: 'content' 
      },
      target: {
          type: DataTypes.INTEGER,
          field: 'target',
          defaultValue: 1 // 1 = public / 2 = private
      }
  },
  {
      classMethods: {
          Question.belongsToMany(
              models.users, 
              {
                  through: 'QuestionRecipient',  foreignKey: 'questionId'
              }
          );
          Question.belongsTo(
              models.users, 
              {
                  as: 'Creator',  foreignKey: 'creatorId'
              }
          );
      }
  })
  </code></pre>
  
  <p>/** ARTICLE MODEL **/</p>
  
  <pre><code>module.exports = function(sequelize, DataTypes) {
  var Article = sequelize.define('articles', {
      content: {
          type: DataTypes.TEXT,
          field: 'content' 
      }
  },
  {
      classMethods: {
          Article .belongsTo(
              models.users, 
              {
                  foreignKey: 'userId'
              }
          );
      }
  })
  </code></pre>
  
  <p>/** FEED MODEL **/</p>
  
  <pre><code>module.exports = function(sequelize, DataTypes) {
  var Feed = sequelize.define('feeds', {}, 
  {
      classMethods: {
          associate: function(models) {
              Feed.belongsTo(models.articles, {foreignKey: 'articleId'});
              Feed.belongsTo(models.questions, {foreignKey: 'questionId'});
          }
      }
  }, 
  {
    timestamps: true,
    freezeTableName: true
  });
  
  return Feed;
  };
  </code></pre>
  
  <p>Now I want to get all articles which belong to user 1 and all question created by user 1 and asked to user 1 too ! I have tried this</p>
  
  <pre><code>Feed.findAll({
      attributes: ['id', 'articleId', 'questionId','createdAt', 'updatedAt'],
          include: [{
              model: Article,
              where: { userId: 1 },
              required: false,
              attributes: ['id',  'content', 'createdAt', 'userId'],
              include: [{
                  model: User,
                  attributes: ['id', 'firstName', 'lastName']
              }]
          },
          {
          model: Question,
          attributes: ['id', 'content', 'createdAt', 'creatorId'],
          where: { creatorId: 1 },
          required: false,
          include: [{
              model: User,
              as: 'Creator'
              attributes: ['id', 'alias', 'nom', 'prenom'],
              where: { id: 1 }
          }]
      }]
  </code></pre>
  
  <p>But it returns an empty array</p>
  
  <p>How to manage this please ?</p>