feat: add dockerfile with the readme

README.md

@@ -1,2 +1,13 @@
 # isolated-claude-code
 
+1. Build the docker image. `docker build -t claude-code `
+2. Run the container `docker run --rm -it -v "$(git rev-parse --show-toplevel 2>/dev/null || pwd)":/app -v "$HOME/.claude":/root/.claude claude-code`
+
+You can also add a shell alias:
+
+```
+alias claude='docker run --rm -it \
+  -v "$(git rev-parse --show-toplevel 2>/dev/null || pwd)":/app \
+  -v "$HOME/.claude":/root/.claude \
+  claude-code'
+```