title: Is there no option to map the column name in sequelize model
body: <p>I have a given database with long, cumbersome columnnames. Isn't there any way to map the tablenames to shorter and more descriptive propertyNames in the model ? 
  something like</p>
  
  <pre><code>var Employee = sql.define('Employee', {
      id : {type : Sequelize.INTEGER , primaryKey: true, map : "veryLongNameForJustTheId"}
  },{
       tableName: 'cumbersomeTableName',
       timestamps: false
  });;
  </code></pre>