create contribution docs

CONTRIBUTING.md

@@ -0,0 +1,57 @@
+# Welcome to the contributing guide
+
+Contributions are always welcome.
+
+If you have an idea for improvement or think something is wrong please create an issue in our [Issue Tracker](https://github.com/Viva-con-Agua/vite-plugin-runtime-config/issues).
+
+# Build and Release Infrastructure docs
+
+This section documents how the build system of this project is configured and explains why it was done so.
+It also explains how new releases can be created.
+
+## Builds
+
+The distribution of this package include a few different kinds of artifacts.
+Their build scripts are defined inside the [package.json](./package.json) and tied together under one script simply called `build`.
+This will produce the following assets:
+
+-   `build:compile_ts` produces `dist/*.js` and `dist/*.d.ts`
+
+    This script compiles typescript (configured via [tsconfig.json](./tsconfig.json)) using the normal typescript compiler to produce EcmaScript module javascript as well as corresponding declaration files.
+    EcmaScript modules are the most recent and recommended module format which is why they are used.
+
+-   `build:bundle_plugin_entry` produces `dist/index.cjs`
+
+    In addition to EcmaScript module code, [index.ts](./src/index.ts) which forms the vite plugin entrypoint is also bundled into one CommonJS module.
+    This is required because most vue starter project configure typescript to resolve imports from `vite.config.ts` as node modules which currently still requires the CommonJS format.
+
+-   `build:bundle_patch_script` produces `dist/assets/patch_runtime_config.js`
+
+    This is the patch script that gets emitted when a user calls `vite build`.
+    It is generated from [script_entrypoint.ts](./src/script_entrypoint.ts) and does not require any external dependencies since everything is bundled into the script.
+    This is to make the script as portable as possible while still using the same source code ([patch_html.ts](./src/patch_html.ts)) as is used when running vite during development.
+
+-   `build:bundle_patch_bin:*` produces `dist/assets/patch_runtime_config.*.bin`
+
+    These are binary programs that not only bundle javascript dependencies but also nodejs itself.
+    They are required if a user wishes to perform configuration key replacement in an environment where node is not installed.
+    The build script generates these binaries using _pkg_ from `dist/assets/patch_runtime_config.js`.
+
+## Releases
+
+Releases are automatically performed via GitHub actions (workflow source [here](./.github/workflows/release.yml)) whenever a tag is pushed.
+It also appends the tag subject and body as release body.
+
+To author a release, the following steps need to be performed locally:
+
+1. Bump version in [package.json](./package.json)
+2. Create a commit with the bumped version.
+3. Create git tag with the following command where _X.X.X_ is the new version.
+    ```shell
+    git tag -a vX.X.X
+    ```
+4. Push the commit as well as the tag.
+    ```shell
+    git push
+    git push --tags
+    ```

README.md

@@ -104,3 +104,10 @@ You can look in there for inspiration.
 ## Api
 
 The most relevant API for users are [plugin options](./src/options.ts), [testing utilities](./src/testing.ts) and [replacer program arguments](./src/script_entrypoint.ts).
+
+Additionally, the whole project is authored in typescript and type declaration files are distributed as part of our releases.
+Your IDE should pick this up pretty well and offer you good autocompletion and documentation.
+
+## Contributing
+
+See [CONTRIBUTING.md](./CONTRIBUTING.md) for more details.