Documentation update

[tranfuga25s]

On the Readme.md said:

ALTER TABLE users ADD facebook_id BIGINT(20) UNSIGNED NOT NULL

The problem is that when you update the schema to get into account the new field it will be converted to: 'facebook_id' => array('type' => 'integer', 'null' => false, 'default' => null, 'length' => 20) but in a new creation of the schema will get the field to be INT(20) This causes a problem with the autosave user feature that will create a new entry on the table, but the field of facebook_id will be cutted off.

Please change the documentation to float to let the schema reflect a bigger number in the field. Sorry, I'm an spanish speeker

[tranfuga25s]

Sorry, FLOAT doesn't work either... So, please add a comment that after an schema create or schema update shoud change the field type to double or BIGINT(20).