Add Gentoo instructions to install the package (cli#2389)

zpuskas · mislav · web-flow · commit 3c3ce909a1d8 · 2020-11-11T12:39:22.000+01:00
Co-authored-by: Mislav Marohnić &lt;mislav@github.com&gt;
diff --git a/docs/install_linux.md b/docs/install_linux.md
@@ -101,6 +101,21 @@ Android users can install via Termux:
 pkg install gh
 ```
 
+### Gentoo
+
+Gentoo Linux users can install from the [main portage tree](https://packages.gentoo.org/packages/dev-util/github-cli):
+
+``` bash
+emerge -av github-cli
+```
+
+Upgrading can be done by updating the portage tree and then requesting an upgrade:
+
+``` bash
+emerge --sync
+emerge -u github-cli
+```
+
 ### Kiss Linux
 
 Kiss Linux users can install from the [community repos](https://github.com/kisslinux/community):
