added initial api views to bookshare; will need to determine what other...

added initial api views to bookshare; will need to determine what other information, if any we wish to expose for the first go round

bookshare/api/views.py

-from django.shortcuts import render
+# standard library imports
+from __future__ import absolute_import, print_function
+# third party imports
+from rest_framework.pagination import PageNumberPagination
+from rest_framework.viewsets import ReadOnlyModelViewSet
+# imports from your apps
+from trades.models import Listing
+from .serializers import ListingSerializer
 
-# Create your views here.
+
+# trades apis
+class ListingPagination(PageNumberPagination):
+    page_size = 100  # number of results per page
+    page_size_query_param = 'page_size'
+    max_page_size = 1000  # so you can retrieve a maximum of 100,000 listings
+
+
+class ListingViewSet(ReadOnlyModelViewSet):
+    queryset = Listing.objects.all().order_by('-created')
+    serializer_class = ListingSerializer
+    pagination_class = ListingPagination