gh-auth: add page (#4839)

pages/common/gh-auth.md

@@ -0,0 +1,24 @@
+# gh auth
+
+> Authenticate with a GitHub host from the command line.
+> More information: <https://cli.github.com/manual/gh_auth>.
+
+- Login with interactive prompt:
+
+`gh auth login`
+
+- Login with a token from standard input (created in https://github.com/settings/tokens):
+
+`echo {{your_token}} | gh auth login --with-token`
+
+- Check if you are logged in:
+
+`gh auth status`
+
+- Log out:
+
+`gh auth logout`
+
+- Login with a specific GitHub Enterprise Server:
+
+`gh auth login --hostname {{github.example.com}}`