Hide follow request buttons after responding

Fixes #106

fedireads/templates/snippets/follow_request_buttons.html

@@ -1,3 +1,5 @@
+{% load fr_display %}
+{% if request.user|follow_request_exists:user %}
 <form action="/accept_follow_request/" method="POST">
     {% csrf_token %}
     <input type="hidden" name="user" value="{{ user.username }}">
@@ -8,3 +10,4 @@
     <input type="hidden" name="user" value="{{ user.username }}">
     <button type="submit" class="warning">Delete</button>
 </form>
+{% endif %}

fedireads/templatetags/fr_display.py

@@ -88,6 +88,20 @@ def get_user_liked(user, status):
         return False
 
 
+@register.filter(name='follow_request_exists')
+def follow_request_exists(user, requester):
+    ''' see if there is a pending follow request for a user '''
+    try:
+        models.UserFollowRequest.objects.filter(
+            user_subject=requester,
+            user_object=user,
+        ).get()
+        return True
+    except models.UserFollowRequest.DoesNotExist:
+        return False
+
+
+
 @register.simple_tag(takes_context=True)
 def shelve_button_identifier(context, book):
     ''' check what shelf a user has a book on, if any '''