feat: add install instructions #2

Author: zaucy

README.md

@@ -0,0 +1,16 @@
+# Ecsact Unreal Integration
+
+:warning: under heavy development
+
+## Install
+
+The Ecsact Unreal Integration is **not** available in the unreal marketplace as of yet. Instead we recommend adding a git submodule in your `Plugins` directory.
+
+```bash
+# make sure to CD into your project folder that contains your .uproject
+cd path/to/your/project/root
+
+# add ecsact integration as a submodule in Plugins/Ecsact
+git submodule add https://github.com/ecsact-dev/ecsact_unreal Plugins/Ecsact
+```
+