Add ARCHITECTURE, CODE_OF_CONDUCT, CONTRIBUTING files + flesh out the README.

README.md

@@ -32,10 +32,39 @@
 
 -----
 
-## Gold sponsors
+## What is Rapier?
+
+Rapier is a set of 2D and 3D physics engines for games, animation, and robotics. It is built in Rust
+by the [Dimforge](https://dimforge.com) organization. It is forever free and open-source!
+
+## Roadmap
+We update our roadmap at the beginning of each year. Our 2021 roadmap can be seen
+[there](https://www.dimforge.com/blog/2021/01/01/physics-simulation-with-rapier-2021-roadmap/#rapier-roadmap-for-2021).
+
+## Getting started
+The easiest way to get started with Rapier is to:
+1. Read the [user-guides](https://www.rapier.rs/docs/).
+2. Play with the examples: `cargo run --release --bin all_examples2` and `cargo run --release --bin all_examples3`.
+   Their source code are available on the `examples2d/` and `examples3d/` directory.
+3. Don't hesitate to ask for help on [Discord](https://discord.gg/vt9DJSW), or by opening an issue on GitHub.
+  
+## Resources and discussions
+- [Dimforge](https://dimforge.com): See all the open-source projects we are working on. Follow our announcements
+  on our [blog](https://www.dimforge.com/blog).
+- [User guide](https://www.rapier.rs/docs/): Learn to use Rapier in your project by reading the official User Guides.
+- [Discord](https://discord.gg/vt9DJSW): Come chat with us, get help, suggest features, on Discord!
+- [NPM packages](https://www.npmjs.com/search?q=%40dimforge): Check out our NPM packages for Rapier, if you need to
+  use it with JavaScript/Typescript.
+
+Please make sure to familiarize yourself with our [Code of Conduct](CODE_OF_CONDUCT.md)
+and our [Contribution Guidelines](CONTRIBUTING.md) before contributing or participating in
+discussions with the community.
+
+
+## Platinum sponsors
 Rapier is supported by:
 <p>
   <a href="https://embark-studios.com">
-    <img src="https://www.embark.dev/img/logo_black.png" width="301px">
+    <img src="https://www.embark.dev/img/logo_black.png" width="400px">
   </a>
 </p>