readme: Be specific about SSL cert

Current instructions about SSL certificate are pretty much open
to interpretation, and users might probably end up not adding all
the required domain names, causing gitpod instance to fail on startup.

This updates the guide to be more clear

Signed-off-by: Tarun Pothulapati <[email protected]>

Author: Pothulapati

README.md

@@ -6,14 +6,20 @@ Before starting the installation process, you need:
 
 - An AWS account with Administrator access
   - [Create one now by clicking here](https://aws.amazon.com/getting-started/)
-- A SSL Certificate created with [AWS Certificate Manager](https://aws.amazon.com/en/certificate-manager/)
 - AWS credentials set up. By default, those configs are present in `$HOME/.aws/`.
 - [eksctl](https://eksctl.io/) config file describing the cluster.
   - Here is an [eks-cluster.yaml](eks-cluster.yaml) you can use as example.
 - A `.env` file with basic details about the environment.
   - We provide an example of such file [here](.env.example).
 - [Docker](https://docs.docker.com/engine/install/) installed on your machine, or better, a Gitpod workspace :)
 
+### SSL Certificate
+
+Create a public SSL/TLS certificate with [AWS Certificate Manager](https://aws.amazon.com/en/certificate-manager/),
+valid for the `<domain>`, `*.ws.<domain>` and `*.<domain>` Domain names.
+
+Once the certificate is issued and verified, Update the `CERTIFICATE_ARN` field in the `.env` file accordingly.
+
 ### Choose an Amazon Machine Image (AMI)
 
 Please update the `ami` field in the [eks-cluster.yaml](eks-cluster.yaml) file with the proper AMI ID for the region of the cluster.