Add contribution documentation in README.md

README.md

@@ -1,6 +1,15 @@
-<div>
-  <img src="https://i.imgur.com/9jkn0cO.png" align="left">
-  <img src="https://i.imgur.com/9jkn0cO.png" align="right">
-</div>
-<h1 align="center">GregTech Intergalactical</h1>
-<h3 align="center">The <i>Approved</i> Continuation of GregTech 5 Unofficial</h3
+# ![GregTech logo](https://i.imgur.com/9jkn0cO.png) &mdash; AntimatterAPI &mdash; ![GregTech logo](https://i.imgur.com/9jkn0cO.png) 
+
+The building blocks of GregTech Intergalactical.
+
+## Contribution
+
+Constribution is welcomed, join our [Discord](https://discord.gg/9kM4bRj) to get in touch!
+
+To clone this repository, make sure you also clone the submodules:
+
+```
+$ git clone --recurse-submodules https://github.com/GregTech-Intergalactical/AntimatterAPI.git
+```
+
+*Note: we're currently working on code documentation, don't be afraid.*