bash v4 is required
* bash v4 is required
copied other tools from
* serving --> eventing
* Update DEVELOPMENT.md
* updated based on comments
* fixed based on review comments
* remove trailing whitespace
@@ -26,7 +26,20 @@ Before submitting a PR, see also [contribution guidelines](./CONTRIBUTING.md).
### Requirements
-You must have [`ko`](https://github.com/google/ko) installed.
+You must install these tools:
+
+1. [`go`](https://golang.org/doc/install): The language `Knative Eventing` is
+ developed with (version 1.15 or higher)
+1. [`git`](https://help.github.com/articles/set-up-git/): For source control
+1. [`ko`](https://github.com/google/ko): For building and deploying container
+ images to Kubernetes in a single command.
+1. [`kubectl`](https://kubernetes.io/docs/tasks/tools/install-kubectl/): For
+ managing development environments.
+1. [`bash`](https://www.gnu.org/software/bash/) v4 or higher. On macOS the
+ default bash is too old, you can use [Homebrew](https://brew.sh) to install a
+ later version. For running some automations, such as dependencies updates and
+ code generators.
+
### Create a cluster and a repo
