Add uuid documentation

Author: iWader

uuid.md

@@ -0,0 +1,61 @@
+---
+currentMenu: uuid
+---
+
+# UUID
+
+The uuid trait automatically generates uuids for your Eloquent models.
+
+- [Usage](#usage)
+    - [Primary Key](#primary-key)
+- [Custom Column](#custom-column)
+
+## Usage
+
+Usage is as simple as adding a uuid column to your database and using the trait on your model.
+
+```php
+Schema::table('users', function (Blueprint $table)
+{
+    $table->uuid('uuid');
+});
+```  
+
+```php
+use Laratools\Eloquent\Uuid;
+
+class User extends Model
+{
+    use Uuid;
+}
+```
+
+Now, whenever you save a new model, a uuid will be generated.
+
+#### Primary Key
+
+Using a uuid as the primary key is as simple as setting auto-increments on your model to false.
+
+```php
+use Laratools\Eloquent\Uuid;
+
+class User extends Model
+{
+    use Uuid;
+    
+    public $incrementing = false;
+}
+```
+
+## Custom Column
+
+By default the trait will assume a column name of `uuid`, however you can customise this on a per-model basis by defining the `UUID_COLUMN` constant on your model.
+
+```php
+class User extends Model
+{
+    use Uuid;
+    
+    const UUID_COLUMN = 'id';
+}
+```