squads: don't allow ineligible users into squad (#718)

Co-authored-by: recursivetree <recursivetreemail@gmail.com>

Author: Crypta-Eve

src/Http/Controllers/Squads/ApplicationsController.php

@@ -64,6 +64,10 @@ public function show(Squad $squad, int $id)
      */
     public function store(Request $request, Squad $squad)
     {
+        if(!$squad->isUserEligible(auth()->user())) {
+            return redirect()->back()->with('error','You are not eligible for this squad!');
+        }
+
         // in case the squad is manual and does not contain any moderator
         // applications are self-approved.
         if ($squad->type == 'manual' && $squad->moderators->isEmpty()) {
@@ -108,6 +112,10 @@ public function approve(Squad $squad, int $id)
     {
         $application = SquadApplication::with('squad', 'user')->find($id);
 
+        if(!$squad->isUserEligible($application->user)) {
+            return redirect()->back()->with('error','The applicant is not eligible for this squad!');
+        }
+
         $squad->members()->save($application->user);
 
         $message = sprintf('Approved application from %s into squad %s.',