doc: add reference to common-template-copier

README.md

 # gitlab-ci-tools
-This project includes reuseable GitLab-CI jobs for the GitLab Dedicated Project
+This project includes reuseable GitLab-CI jobs for the GitLab Dedicated Project.
+
+Setting up a new project? Use the [project template](#project-template).
 ## Developer Setup
@@ -40,3 +42,9 @@ Alternatively to using the templates above, you can include the following indivi
 | [`terraform-format.yml`](./terraform-format.md)| Runs [`terraform fmt`](https://www.terraform.io/cli/commands/fmt) to ensure that all Terraform files are correctly formatted. |
 | [`terraform-validate.yml`](./terraform-validate.md) | Runs [`terraform validate`](https://www.terraform.io/cli/commands/validate) to ensure that all Terraform files are valid. |
 | [`tflint.yml`](./tflint.md) | Runs [`tflint`](https://github.com/terraform-linters/tflint) across all directories that contain `*.tf` files. |
+
+## Project Template
+
+`common-ci-tasks` favours convention-over-configuration, and expects configuration files and some directories to be configured in a certain way. The quickest way to get going on a new project is to use the `common-template-copier` project template to generate a new project based on the conventions expected by these CI tasks.
+
+Instruction on usage at: <https://gitlab.com/gitlab-com/gl-infra/common-template-copier>.