Update README.md

Author: donatj

README.md

@@ -3,3 +3,11 @@
 ![CI](https://github.com/NoteOf/noteof-cli/workflows/CI/badge.svg)
 [![Go Report Card](https://goreportcard.com/badge/github.com/NoteOf/noteof-cli)](https://goreportcard.com/report/github.com/NoteOf/noteof-cli)
 [![GoDoc](https://godoc.org/github.com/NoteOf/noteof-cli?status.svg)](https://godoc.org/github.com/NoteOf/noteof-cli)
+
+## Install
+
+### From Source
+
+```shell
+$ go install github.com/NoteOf/noteof-cli/cmd/note@latest
+```