Add ability to tie locations to companies

Locations are the last big part of the application that can't be tied to companies.
This can be a problem with FullMultipleCompanySupport, because you can't restrict the visibility of locations to the company of the users.

In order to change this, add a company_id to the locations table and wire everything up in the views and controllers.
Aditionally add a new formatter to filter the locations to a specific company, like it is done for assets.

Locations are properly scoped to the users company if FullMultipleCompanySupport is enabled.
If a parent location of a location has a different company than the user, the location does not show up.

app/Models/Location.php

@@ -22,6 +22,7 @@ class Location extends SnipeModel
     protected $presenter = \App\Presenters\LocationPresenter::class;
     use Presentable;
     use SoftDeletes;
+    use CompanyableTrait;
 
     protected $table = 'locations';
     protected $rules = [
@@ -34,11 +35,13 @@ class Location extends SnipeModel
         'zip'           => 'max:10|nullable',
         'manager_id'    => 'exists:users,id|nullable',
         'parent_id'     => 'nullable|exists:locations,id|non_circular:locations,id',
+        'company_id'    => 'integer|nullable|exists:companies,id',
     ];
 
     protected $casts = [
         'parent_id'     => 'integer',
         'manager_id'    => 'integer',
+        'company_id'    => 'integer',
     ];
 
     /**
@@ -72,6 +75,7 @@ class Location extends SnipeModel
         'currency',
         'manager_id',
         'image',
+        'company_id',
     ];
     protected $hidden = ['user_id'];
 
@@ -90,7 +94,8 @@ class Location extends SnipeModel
      * @var array
      */
     protected $searchableRelations = [
-      'parent' => ['name'],
+      'parent'  => ['name'],
+      'company' => ['name']
     ];
 
 
@@ -214,6 +219,17 @@ class Location extends SnipeModel
             ->with('parent');
     }
 
+    /**
+    * Establishes the locations -> company relationship
+    *
+    * @author [T. Regnery] [<tobias.regnery@gmail.com>]
+    * @since [v7.0]
+    * @return \Illuminate\Database\Eloquent\Relations\Relation
+    */
+    public function company()
+    {
+        return $this->belongsTo(\App\Models\Company::class, 'company_id');
+    }
 
     /**
      * Find the manager of a location
@@ -313,4 +329,17 @@ class Location extends SnipeModel
     {
         return $query->leftJoin('users as location_user', 'locations.manager_id', '=', 'location_user.id')->orderBy('location_user.first_name', $order)->orderBy('location_user.last_name', $order);
     }
+
+   /**
+    * Query builder scope to order on company
+    *
+    * @param  \Illuminate\Database\Query\Builder  $query  Query builder instance
+    * @param  text                              $order       Order
+    *
+    * @return \Illuminate\Database\Query\Builder          Modified query builder
+    */
+    public function scopeOrderCompany($query, $order)
+    {
+        return $query->leftJoin('companies as company_sort', 'locations.company_id', '=', 'company_sort.id')->orderBy('company_sort.name', $order);
+    }
 }