Add basic REST functionality for Instance

Added GET and POST endpoints for Instance

recircle/instance/serializers.py

+from rest_framework import serializers
+
+from .models import Instance
+
+
+class InstanceSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = Instance
+        fields = ("name",
+                  "description",
+                 )

recircle/instance/urls.py

@@ -3,5 +3,5 @@ from django.urls import path
 from . import views
 
 urlpatterns = [
-    path('', views.index, name='index'),
+    path('', views.instance_list),
 ]
\ No newline at end of file

recircle/instance/views.py

-from django.http import HttpResponse
+from django.http import HttpResponse, JsonResponse
+from django.views.decorators.csrf import csrf_exempt
+from rest_framework.renderers import JSONRenderer
+from rest_framework.parsers import JSONParser
+from instance.models import Instance
+from instance.serializers import InstanceSerializer
 
 
 def index(request):
     return HttpResponse("Hello, world. You're at the instance index.")
+
+@csrf_exempt
+def instance_list(request):
+    """
+    List all instances, or create a new one.
+    """
+    if request.method == 'GET':
+        instances = Instance.objects.all()
+        serializer = InstanceSerializer(instances, many=True)
+        return JsonResponse(serializer.data, safe=False)
+
+    elif request.method == 'POST':
+        data = JSONParser().parse(request)
+        serializer = InstanceSerializer(data=data)
+        if serializer.is_valid():
+            serializer.save()
+            return JsonResponse(serializer.data, status=201)
+        return JsonResponse(serializer.errors, status=400)