Update scaling config

Author: addyosmani

app.yaml

@@ -8,6 +8,5 @@ handlers:
   secure: always
 skip_files:
   - ^(.*/)?.*/node_modules/.*$
-automatic_scaling:
-  min_num_instances: 15
-  max_num_instances: 100
+manual_scaling:
+  instances: 20