ADD: (CONTRIBUTING.md) added text about compiling/build

Author: neo-garaix

CONTRIBUTING.md

@@ -0,0 +1,39 @@
+
+The documentation is available on [docs.rs](https://docs.rs/proj4rs/) and the demo on [docs.3liz.org](https://docs.3liz.org/proj4rs/).
+
+## Compiling for WASM
+
+Install [wasm-pack](https://rustwasm.github.io/wasm-pack/book/)
+
+```bash
+wasm-pack build --target web --no-default-features
+```
+
+Or if you have installed [cargo-make](https://sagiegurari.github.io/cargo-make/), use the following
+command:
+
+```bash
+cargo make wasm
+```
+
+### Running the WASM example
+
+There is a [`index.html`] file for testing the WASM module in a navigator.
+
+For security reasons, you need to run it from a server.
+You can start a Python server with the following command:
+
+```bash
+python3 -m http.server
+```
+
+The server will automatically serve the `index.html` file in the current directory.
+
+
+## Build for npm
+
+```
+cargo make wasm_bundle
+```
+
+This will create a npm bundler package in pkg-bundler

README.md

@@ -99,4 +99,6 @@ let point = new Proj.Point(2.0, 1.0, 0.0);
 Proj.transform(from, to, point);
 ```
 
+## Contributing
 
+You can contribute to this library by going on the [proj4rs](https://github.com/3liz/proj4rs/) repository