Add cargo install --git option to installation instructions (#31)

README.md

@@ -27,6 +27,12 @@ claude-chill sits between your terminal and Claude Code:
 
 ## Installation
 
+```bash
+cargo install --git https://github.com/davidbeesley/claude-chill
+```
+
+Or, if you've cloned the repository locally:
+
 ```bash
 cargo install --path crates/claude-chill
 ```