title: find records in sequelize seeds
body: <p>I've been trying to write some seeds for my project, but I've ran into a bit of a snag.</p>
  
  <p>I've got a <code>many-to-many</code> relation with my <code>users</code> and <code>roles</code> table. So, when I'm seeding the database I need to add a record with correct ids into my join table. In order to do that I need to find user by <code>email</code> and role by <code>name</code> and get the <code>ids</code> and that's the problem. I can't find any good documentation on the <a href="http://docs.sequelizejs.com/en/latest/" rel="noreferrer">sequelize site</a>. I'm using the <a href="https://github.com/sequelize/cli" rel="noreferrer">sequelize-cli</a> for the seeding and migrating things. I get as a parameter a <code>queryInterface</code>, but I can't find any example or mention what this thing can actually do. Just some simple examples just got me through the migrating (somehow) and what I was able to find on google.</p>
  
  <p>I've resolved this by using a "dirty trick" I'd say...</p>
  
  <pre><code>// user_seeds.js
  up: function (queryInterface, Sequelize) {
    return queryInterface.bulkInsert(table, [{
      id: 1,
      name: 'John doe',
      email: 'john@doe.com',
      created_at,
      updated_at
  }], {});
  
  // roles_seeds.js
  up: function (queryInterface, Sequelize) {
    return queryInterface.bulkInsert(table, [{
      id: 1,
      name: 'admin',
      created_at,
      updated_at
    }, {
      id: 2,
      name: 'user',
      created_at,
      updated_at
  }]);
  
  //user_roles_seeds.js
  up: function (queryInterface, Sequelize) {
      return queryInterface.bulkInsert(table, [{
      employee_id: 1,
      role_id: 1
    }]);
  },
  </code></pre>
  
  <p>Don't like this solution since it may be troublesome in the future should I'd want to run the seeds again and forget about how this works. There should be a way for me to query the database using this <code>queryInterface</code>. I was wondering if one of you had ran into this issue and solved it, if so, please share.</p>