allow table object with no physical table

this allows by calling "$this->table(false);" to have an physical table
this you can use for example for login or contact or feedback form validation

you could even do decimal validation by specifying the exact column type

for example:
```
        $this->table(false);
        $this->schema()->addColumn('length', [
            'type' => 'decimal',
            'length' => 10,
            'precision' => 2,
            'unsigned' => true,
            'null' => false,
            'default' => null
        ]);
```