Add info on release builds (#180)

README.md

@@ -71,6 +71,14 @@ Running your game locally is very simple:
 
 If you're using [VS Code](https://code.visualstudio.com/), this template comes with a [`.vscode/tasks.json`](./.vscode/tasks.json) file.
 
+<details>
+  <summary>Run release builds</summary>
+
+- Use `cargo run --profile release-native --no-default-features` to run a native release build.
+- Use `trunk serve --no-default-features` to run a web release build.
+
+</details>
+
 <details>
     <summary>(Optional) Improve your compile times</summary>