chart fixes and readme edits

helm/snapdrop/templates/service.yaml

@@ -0,0 +1,13 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ .Release.Name }}
+spec:
+  type: ClusterIP
+  selector:
+    app.kubernetes.io/name: snapdrop
+  ports:
+  - name: http
+    protocol: TCP
+    port: 80
+    targetPort: http