title: CakePHP Migrations - How to specify scale and precision
body: <p>I'm Running CakePhp 2.7 with Migrations Plugin and a Postgresql DB.
  Creating a field of type 'number' and specifying length 15,4 (scale 15, precision 4 - or any length) does not actually create the field with that precision and/or scale.</p>
  
  <pre><code>          ...
   'license_fee' =&gt; array(
     'type' =&gt; 'number',
     'null' =&gt; true,
     'length' =&gt; '15,6',
     'default' =&gt; 0
    ),
          ...
  </code></pre>
  
  <p>The field is created with the correct type (numeric) but with no scale/precision here is the Postgres description of the created field.</p>
  
  <pre><code>license_fee               | numeric | default 0
  </code></pre>
  
  <p>What I was expecting to see is this</p>
  
  <pre><code>license_fee               | numeric(15,6) | default 0
  </code></pre>
  
  <p>I also tried using 'type' => 'decimal' but same happened. This might not be supported by the migrations plugin but I just want to know if anyone knows for sure what's going on.</p>