title: Knex primary key auto increment
body: <p>I'm using knex to create a simple table in postgres database: </p>
  
  <pre><code>function up(knex, Promise) {
  return knex.schema.createTableIfNotExists('communities', (table) =&gt; {
  
      table.increments('id').primary().unsigned();
  
      table.string('name', 255).notNullable();
      table.string('slug', 100).notNullable();
  
      table.timestamp('createdAt').defaultTo( knex.fn.now() );
      table.timestamp('updatedAt');
  });
  </code></pre>
  
  <p>};</p>
  
  <pre><code>function down(knex, Promise) {
    return knex.schema.dropTableIfExists(tableName);
  };
  
  module.exports = {
      tableName,
      up,
      down
  }
  </code></pre>
  
  <p>My problem is that <code>table.increments('id').primary()</code> creates a primary key that for default value has <code>nextval('communities_id_seq'::regclass)</code> and I can't do an insert without an id (even in raw sql). </p>
  
  <p>Does anyone know how to make the id increment by default?</p>