update readme as a preperation for v4

Author: nstapelbroek

README.md

@@ -2,21 +2,23 @@
 
 # Docker static webserver
 
-A simple alpine based nginx web container that has the ability to insert environment variables. Created to add a bit more configuration flexibility to statically generated front-ends (like webpack builds) without having to re-build your Docker image or use a scripting language.
+A simple nginx docker image that has the ability to insert environment variables. Created so I could re-use an image between prod and staging environments for my frontend builds.
+It replaces environment variables on container startup so you don´t have to rebuild your Docker image or use a server-side language to change some settings.
 
 ## Getting Started
 
-This repository generates the images available on the [Docker hub](https://hub.docker.com/r/nstapelbroek/static-webserver/tags). Using this image for your own project is as simple as creating a Dockerfile with the two lines below: 
+This repository generates the images available on the [Docker hub](https://hub.docker.com/r/nstapelbroek/static-webserver/tags).
+Using this image for your own project is as simple as creating a Dockerfile with the two lines below:
 
 ```Dockerfile
 FROM nstapelbroek/static-webserver:4
 COPY ./your-static-content /var/www
 ``` 
 
-A more modern example where you build your frontend project and ship it with the image:
+A more modern example where you build your frontend project and ship it:
 
 ```Dockerfile
-FROM node:16 as build
+FROM node:18 as build
 WORKDIR /opt/project
 
 COPY package.json package-lock.json /opt/project/
@@ -25,7 +27,7 @@ RUN npm ci
 COPY . /opt/project
 RUN npm run build
 
-FROM nstapelbroek/static-webserver:3
+FROM nstapelbroek/static-webserver:4
 COPY --from=build --chown=nginx:nginx /opt/project/dist /var/www
 ```
 
@@ -41,13 +43,13 @@ For example, given this HTML in a file located at `/var/www/index.html`
 </p>
 ```
 
-Will result in the image below when you run your image with `-e BACKEND_URL=https://api.someproject.com`.
+And building & running this with an environment variable passed in docker run (`docker run -p 8080:80 -e BACKEND_URL=https://api.someproject.com myimage:latest`), you'll end up with:
 
 ![result](https://user-images.githubusercontent.com/3368018/27512102-48ae27aa-5936-11e7-824a-92ca12d5334f.png)
 
 ### What tag should I use?
 
-To prevent sudden BC-breaks you should avoid using the `latest` tag when building upon this image (or any image for that matter). 
+To prevent sudden BC-breaks you should avoid using the `latest` tag when building upon this image (or any image for that reason).
 I'm using [Semver](https://semver.org/) as a base for versioning schematics. Due to the small functionality of this container I'm considering the following changes as "incompatible API changes": 
 
 - Altered behavior at clients, for example due to changes in cache-headers
@@ -61,7 +63,7 @@ You should use the latest available tag in [at in the registry](https://hub.dock
 Due to the simple approach of finding & replacing the keywords there are some limitations:
 - Please make sure your environment keys do not contain special characters. Only `a-z`, `A-Z`, `0-9` and `_` are recommended.
 - By default, the script only changes files located in `/var/www`. You can change this by setting the `NGINX_ENVSUBST_WWW_DIR` environment variable. 
-- The container does not change files on the fly, so if you can't avoid mounting volumes be carefull.
+- The project is not meant as a development environment. Don´t mount your code in here as it will only change envioronment variables on the first starutp.
 
 ## License
 
@@ -70,4 +72,6 @@ This project is licensed under the MIT License - see the [LICENSE](LICENSE) file
 ## Acknowledgments
 
 * [nginx dockerfiles](https://github.com/nginxinc/docker-nginx) for creating a stable base image
+* [h5bp server configs](https://github.com/h5bp/server-configs-nginx) for providing the nginx config
 * [html5up](html5up.net) for providing the template used in the placeholder page
+* [envsubst](https://linux.die.net/man/1/envsubst) for doing the replacements