Fix invoice generation and other minor cosmetic items

app/Models/Account.php

@@ -91,6 +91,11 @@ class Account extends Model implements IDs
 		return $active ? $query->active() : $query;
 	}
 
+	public function site()
+	{
+		return $this->belongsTo(Site::class);
+	}
+
 	public function taxes()
 	{
 		return $this->hasMany(Tax::class,'country_id','country_id');