Add section on usage

README.md

@@ -11,3 +11,17 @@ Because all parameters are passed to the TailwindCSS executable, twshim itself i
 * `TWROOT` is the directory for downloaded TailwindCSS executables, e.g. `$HOME/.twshim/downloads`.
 
 twshim uses `runtime.GOOS` and `runtime.GOARCH` to decide which executable to download.
+
+## Usage
+
+You can use `go run` to invoke twshim if you want to quickly execute a specific version of TailwindCSS CLI.
+
+```shell
+TWTAG=v3.2.4 TWROOT=$HOME/.twshim/downloads go run github.com/ngrash/twshim/cmd/[email protected]
+```
+
+You can also use `go get` to add twshim to your application and use the `twshim` package from your code.
+
+```shell
+go get github.com/ngrash/[email protected]
+```