/**
  * Remove the specified resource from storage.
  *
  * @param  int  $id
  * @return \Illuminate\Http\Response
  */
 public function destroy($id)
 {
     // check if account exists
     $account = Account::find($id);
     if ($account === null || $account->user_id != Auth::user()->id) {
         // stuff to pass into view
         $title = "Error";
         $errmsg = "The account does not exist.";
         return view('errors.error', compact('errmsg', 'title', 'heading'));
     }
     // start database transaction
     DB::transaction(function () use($account) {
         // delete account
         $account->delete();
         // get obsolete transfers
         $transfers = Transfer::whereNull('account_from')->whereNull('account_to')->get();
         // delete transfers
         foreach ($transfers as $transfer) {
             $transfer->delete();
         }
     });
     // flash message
     session()->flash('flash_message', 'Account deleted successfully.');
     // redirect to accounts
     return redirect()->route('accounts.index');
 }