show the correct name when creating reimbursement

src/backoffice/templates/reimbursement_create.html

@@ -2,7 +2,7 @@
 {% load bootstrap3 %}
 
 {% block content %}
-<h3>Create Reimbursement for User {{ user }}</h3>
+<h3>Create Reimbursement for User {{ reimbursement_user }}</h3>
 
 <div class="panel panel-default">
   <div class="panel-heading">

src/backoffice/views.py

@@ -325,6 +325,7 @@ class ReimbursementCreateView(CampViewMixin, EconomyTeamPermissionMixin, CreateV
             paid_by_bornhack=False,
         )
         context['total_amount'] = context['expenses'].aggregate(Sum('amount'))
+        context['reimbursement_user'] = self.reimbursement_user
         return context
 
     def form_valid(self, form):