Improvement: Documentation (#42)

* Updated docs

* This is the most of it

* kscale to nightscaler

* fix shields

* Update README.md

Co-authored-by: Peter Brøndum <[email protected]>

---------

Co-authored-by: Peter Brøndum <[email protected]>

README.md

@@ -1,12 +1,69 @@
 # Nightscaler
 
+![GitHub release (latest SemVer)](https://img.shields.io/github/v/release/bestseller/nightscaler?sort=semver&style=flat-square)
+![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/bestseller/nightscaler?style=flat-square)
+
+Nightscaler is an application designed to annotate Kubernetes namespaces based
+on Pub/Sub messages. It serves as an extension to [kube-downscaler](https://codeberg.org/hjacobs/kube-downscaler), providing
+additional functionality for managing forced-uptime periods within namespaces.
+
+## Overview
+
+Kubernetes clusters often utilize kube-downscaler to scale down namespaces and
+conserve resources. However, this scaling-down process can render services
+within a namespace temporarily inaccessible. Nightscaler addresses this
+limitation by enabling the annotation of forced-uptime periods, instructing
+kube-downscaler to scale up the affected namespaces during specific time frames.
+
+## Features
+
+- Annotations based on Pub/Sub messages: Nightscaler listens for Pub/Sub
+  messages and expects specific attributes (`action`, `namespace`, `cluster`,
+  and `duration`) to be present in each message.
+- Forced-uptime annotations: When a relevant Pub/Sub message is received,
+  nightscaler adds an annotation to the targeted namespace, specifying a
+  forced-uptime period using the `downscaler/force-uptime` key-value pair.
+- Integration with kube-downscaler: The annotations created by nightscaler
+  trigger kube-downscaler to scale up the namespace during the annotated
+  forced-uptime period, ensuring the availability of services.
+
+## Getting Started
+
+### Prerequisites
+
+- Kubernetes cluster
+- Google Cloud Pub/Sub
+- Service Account with Pub/Sub permissions and Workload Identity enabled
+- Helm
+
+### Installation
+
+To be added.
+
 ## Running locally
 
-First you need to start the Pub/Sub emulator, to do so have a look at the [.hack](./.hack/README.md) folder.
+First you need to start the Pub/Sub emulator, to do so have a look at the
+[.hack](./.hack/README.md) folder.
 
 ```shell
 export PUBSUB_PROJECT_ID=es-standalone-cb21
 export PUBSUB_EMULATOR_HOST=localhost:8085
 
 go run .
 ```
+
+### Usage
+
+1. Create an interface (e.g., a website) that allows users to trigger actions
+   that require forced-uptime periods.
+2. Configure the interface to send Pub/Sub messages with the required attributes
+   (action, namespace, cluster, and duration) to the nightscaler application.
+3. Nightscaler will receive the Pub/Sub messages, process them, and add
+   annotations to the specified namespaces accordingly.
+4. kube-downscaler will respond to the annotations created by nightscaler,
+   scaling up the namespaces during the forced-uptime periods.
+
+## Contributing
+
+Contributions are welcome! If you have any ideas, suggestions, or bug reports,
+please open an issue or submit a pull request.