docs: add Before run Shipjs section (#427)

* docs: add Before run Shipjs section

* chore: remove .tool-versions

GUIDE.md

@@ -4,6 +4,7 @@
 
 - [Installation](#installation)
  - [Install `hub`](#install-hub)
+ - [Before run Shipjs](#before-run-shipjs)
  - [Dry Mode](#dry-mode)
 - [On your local machine](#on-your-local-machine)
 - [Automate Part 3 (`shipjs trigger`) on your CI](#automate-part-3-shipjs-trigger-on-your-ci)
@@ -75,6 +76,24 @@ You can get an access token from [here](https://github.com/settings/tokens).
 
 Or you can simply run `hub api user`, follow the instruction and it will generate the token and write the config file for you.
 
+### Before run Shipjs
+Shipjs compares previous version.
+
+Before run `shipjs` commands, you need release first version by yourself. 
+
+Let's release first version with [yarn version](https://yarnpkg.com/en/docs/cli/version) commands.
+
+In this situation, your branch is `master` and your package version is `0.0.0`.
+You want to release `0.0.1` at `master` branch.
+
+```bash
+yarn version --patch
+git push origin master
+git push --tags
+```
+
+With this you can use `shipjs` commands.
+
 ### Dry Mode
 
 If you're not sure, you can always run commands in dry mode.