chore: Update README

README.md

@@ -1 +1,21 @@
 # Slopvivors
+
+Not AI-slop, but just regular slop survivors game.
+
+# Build
+
+Build using nix:
+
+```console
+$ nix build .#\slopvivors
+```
+
+# Development
+
+Use nix to setup development environment. Contains godot and other useful tools.
+
+```console
+$ nix develop
+$ godot project.godot
+```
+