document installation

README.md

@@ -9,7 +9,11 @@ It adds all named files or files recursively under named directories at the
 path specified. The output file provides an http.FileSystem interface with
 zero dependencies on packages outside the standard library.
 
-Usage:
+## Installation
+
+`go get -u github.com/mjibson/esc`
+
+## Usage
 
 `esc [flag] [name ...]`
 
@@ -89,4 +93,4 @@ func main() {
 
 You can see worked example in [example](example) dir
 just run it as
-`go run example/main.go example/static.go`
+`go run example/main.go example/static.go`