Prepare for an initial release

.github/workflows/ci.yml

@@ -29,3 +29,5 @@ jobs:
       run: rustup update stable && rustup default stable
     - name: Check formatting
       run: cargo fmt --all -- --check
+    - name: Run unit tests
+      run: cargo test

CHANGELOG.md

@@ -0,0 +1,11 @@
+# Changelog
+
+Notable changes to the `envsub` command are documented in this changelog.\
+The `envsub` command adheres to the [semantic versioning] specification.
+
+## [0.1.0] – 2023-04-12
+
+- Initial release
+
+[0.1.0]: https://github.com/unfunco/envsub/releases/tag/v0.1.0
+[semantic versioning]: https://semver.org

README.md

@@ -1,29 +1,44 @@
-# 🌳 envsub
+# envsub
 
-Environment variable substitution with [Twig]-inspired transformers.
+Environment variable substitution.
 
 ## Getting started
 
 ### Installation
 
+TODO
+
 ### Usage
 
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx
+spec:
+  containers:
+  - image: nginx:${NGINX_VERSION}
+    name: nginx
+    restartPolicy: Never
+```
+
 ```bash
-envsub
+NGINX_VERSION=1.23.4 envsub < manifest.yaml
 ```
 
 ```yaml
-containers:
-- name: example-container
-  image: ${IMAGE|lowercase}
-  ports:
-  - containerPort: ${PORT|default(80)}
+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx
+spec:
+  containers:
+  - image: nginx:1.23.4
+    name: nginx
+    restartPolicy: Never
 ```
 
 ## License
 
 © 2019 [Daniel Morris](https://unfun.co)  
 Made available under the terms of the [Apache License 2.0](LICENSE.md).
-
-[Twig]: https://twig.symfony.com
-[gettext]: https://www.gnu.org/software/gettext/