title: How in graphql get last 3 element
body: <p>How in graphql.js get last 3 created_at element from mysql db table?
  I use sequelize.js</p>
  
  <p>Like this:</p>
  
  <pre><code>query: '{
      elements(last:3){ 
          id
      }
  }'
  </code></pre>
  
  <p>This is my file db.js</p>
  
  <pre><code>const Conn = new Sequelize(/*connection config*/);
  Conn.define('elements', {
      id: {
          type: Sequelize.STRING(36),
          primaryKey: true,
          allowNull: false
      }
  });
  export default Conn;
  </code></pre>
  
  <p>This is my file schema.js</p>
  
  <pre><code>const Query = new GraphQLObjectType({
      name: 'Query',
      description: 'Root query object',
      fields() {
          return {
              elements: {
                  type: new GraphQLList(Element),
                  args: {
                      id: {
                          type: GraphQLString
                      }
                  },
                  resolve (root, args) {
                      return Db.models.elements.findAll({ where: args });
                  }
              }
          }
      }
  });
  </code></pre>