chore: add install, guide in readme

README.md

@@ -2,6 +2,29 @@
 
 Only upgrade specific subset not all modules.
 
+## Install
+
+Should use Go version `>= 1.16`:
+
+```sh
+go install github.com/haunt98/update-go-mod/cmd/update-go-mod@latest
+```
+
+## Usage
+
+Create local file `.deps` or use url depends on your use case:
+
+```sh
+# Default read from .deps
+update-go-mod
+
+# Read from URL
+update-go-mod --deps-url "https://example.txt"
+
+# Don't do anythin
+update-go-mod --dry-run
+```
+
 ## Thanks
 
 - [Managing dependencies](https://go.dev/doc/modules/managing-dependencies)