add /friends endpoint

backend/toolshed/api/friend.py

@@ -0,0 +1,24 @@
+from django.urls import path
+from rest_framework.permissions import IsAuthenticated
+from rest_framework.response import Response
+from rest_framework.views import APIView
+from rest_framework.viewsets import ViewSetMixin
+
+from authentication.signature_auth import SignatureAuthentication
+from toolshed.serializers import FriendSerializer
+
+
+class Friends(APIView, ViewSetMixin):
+    authentication_classes = [SignatureAuthentication]
+    permission_classes = [IsAuthenticated]
+
+    def get(self, request, format=None):  # /api/friends/ #
+        user = request.user
+        friends = user.friends.all()
+        serializer = FriendSerializer(friends, many=True)
+        return Response(serializer.data)
+
+
+urlpatterns = [
+    path('friends/', Friends.as_view(), name='friends'),
+]