Install.rst: Add link to bash/zsh auto-completion

This link explains users about setting-up
tab-completion for coala arguements and bear names.

Closes coala#386

Author: saurabhraj1896

Users/Install.rst

@@ -285,6 +285,13 @@ For x86 python or for x64 python:
 
 Replace "XXX" with the ClangSharp version you received from nuget.
 
+Shell-autocompletion support
+----------------------------
+
+If you are a bash/zsh user , checkout the
+`guide <http://docs.coala.io/en/latest/Users/Shell_Autocompletion.html>`
+for setting-up tab-completion for coala arguements and bear names.
+
 Installation Errors
 -------------------