ARROW-3480: [Website] Fix broken install document for Ubuntu

Author: Kouhei Sutou <kou@clear-code.com>

Closes #2737 from kou/website-fix-ubuntu-install and squashes the following commits:

e4c647eb <Kouhei Sutou>  Fix broken install document for Ubuntu
diff --git a/install.md b/install.md
index d24bad6..39e69d4 100644
--- a/install.md
+++ b/install.md
@@ -81,7 +81,7 @@
 * CentOS 6
 * CentOS 7
 
-Debian GNU/Linux and Ubuntu:
+Debian GNU/Linux:
 
 ```shell
 sudo apt install -y -V apt-transport-https
@@ -96,6 +96,21 @@
 sudo apt install -y -V libarrow-glib-dev # For GLib (C)
 ```
 
+Ubuntu:
+
+```shell
+sudo apt install -y -V apt-transport-https
+sudo apt install -y -V lsb-release
+sudo wget -O /usr/share/keyrings/red-data-tools-keyring.gpg https://packages.red-data-tools.org/$(lsb_release --id --short | tr 'A-Z' 'a-z')/red-data-tools-keyring.gpg
+sudo tee /etc/apt/sources.list.d/red-data-tools.list <<APT_LINE
+deb [signed-by=/usr/share/keyrings/red-data-tools-keyring.gpg] https://packages.red-data-tools.org/$(lsb_release --id --short | tr 'A-Z' 'a-z')/ $(lsb_release --codename --short) universe
+deb-src [signed-by=/usr/share/keyrings/red-data-tools-keyring.gpg] https://packages.red-data-tools.org/$(lsb_release --id --short | tr 'A-Z' 'a-z')/ $(lsb_release --codename --short) universe
+APT_LINE
+sudo apt update
+sudo apt install -y -V libarrow-dev # For C++
+sudo apt install -y -V libarrow-glib-dev # For GLib (C)
+```
+
 CentOS:
 
 ```shell