Fix Admin: UserController and Flight Edit (#1204)

* Fix Admin / UserController

Use Role Repository and `selectBoxList` method instead of the model itself.

* Fix Flight Fields

Added empty/blank option for clearing out the days when needed

* StyleFix

resources/views/admin/flights/fields.blade.php

@@ -199,6 +199,7 @@
             {{ Form::label('days', 'Days of Week') }}
             <span class="description small">optional</span>
             <select id="days_of_week" name="days[]" multiple="multiple" size="7" style="width: 100%;">
+              <option value="">Select Days</option>
               <option value="{{\App\Models\Enums\Days::MONDAY}}"
                 {{in_mask($days, \App\Models\Enums\Days::MONDAY) ? 'selected':'' }}>
                 @lang('common.days.mon')