Fix error "Could not write to bucket" (arithmetric#38)

* Reversed the seventh step with the sixth step

Now aws checks if it has permission to write to the s3 bucket when creating the ses rule, to fix this the user must add the s3 bucket policy before creating the ses rule

* Better way to fix the documentation

* Remove empty space

Author: paolobarbolini

README.md

@@ -127,6 +127,9 @@ Otherwise, you can use an existing one.
 
  - Finish by naming the rule, ensuring it's enabled and that spam and virus
  checking are used.
+ 
+ - If you get an error like "Could not write to bucket", follow step 7 before
+ completing this one
 
  - If you are asked for SES to attempt to add permissions to access
  lambda:InvokeFunction, agree to it.