updated views, url and created template for edit announcement page

widget_princessgabi/announcementboard/templates/announcementboard/announcement-edit.html

+{% extends 'base.html' %}
+
+{% block title %} Edit Announcement {% endblock %}
+{% block header %} 
+    <h1> Edit announcement: </h1> 
+{% endblock %}
+
+{% block body %} 
+<form method='POST'>
+    {% csrf_token %}
+    {{ form }}
+    <input type="Submit" value="Save Changes to Announcement">
+</form>
+{% endblock %}

widget_princessgabi/announcementboard/urls.py

 from django.urls import path
 from . import views
-from .views import (AnnouncementsCreateView,
+from .views import (AnnouncementsCreateView, AnnouncementsUpdateView,
         )
 
 urlpatterns = [
     path('', views.announcement_view, name='announcements'),
     path('announcements/add/', AnnouncementsCreateView.as_view(), name='announcement-add'),
+    path('announcements/<int:pk>/details/edit/', AnnouncementsUpdateView.as_view(), name='announcement-edit'),
 
 ]

widget_princessgabi/announcementboard/views.py

 from django.http import HttpResponse
 from django.shortcuts import render
 
-from django.views.generic.edit import CreateView
+from django.views.generic.edit import CreateView, UpdateView
 
 from .models import Announcement, Reaction
 
@@ -16,3 +16,8 @@ class AnnouncementsCreateView(CreateView):
     model = Announcement
     template_name = 'announcementboard/announcement-add.html'
     fields = '__all__'
+
+class AnnouncementsUpdateView(UpdateView):
+    model = Announcement
+    template_name = 'announcementboard/announcement-edit.html'
+    fields = '__all__'
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