give all users permission to create instances in sandboxes

devops-service/db/mongo/models/project.rb

@@ -93,11 +93,16 @@ module Devops
       def check_authorization user_id, env
         e = self.deploy_env(env)
         return true if user_id == User::ROOT_USER_NAME
+        return true if is_sandbox?
         return e.users.include? user_id
       rescue RecordNotFound => e
         return false
       end
 
+      def is_sandbox?
+        id.start_with?('sandbox-')
+      end
+
 =begin
       def validate!
         super