How to install RabbitVCS on Ubuntu 14.04?

I personally haven't tried it, but there is a version for trusty (14.04) in the PPA, so I guess it should work.

You can always try if it's working (this will install RabbitVCS for CLI (terminal), gedit and Nautilus 3, if you're using another file manager see the full list of packages here):

sudo add-apt-repository ppa:rabbitvcs/ppa
sudo apt-get update
sudo apt-get install rabbitvcs-cli rabbitvcs-core rabbitvcs-gedit rabbitvcs-nautilus3

As @GermanK notes in a comment, you must to restart nautilus for the change to take effect.

And if it doesn't you can remove it:

sudo apt-get remove rabbitvcs-cli rabbitvcs-core rabbitvcs-gedit rabbitvcs-nautilus3

After following the installation steps to install RabbitVCS from the PPA:

$ sudo add-apt-repository ppa:rabbitvcs/ppa
$ sudo apt-get update
$ sudo apt-get install rabbitvcs-nautilus3

# Optional
$ sudo apt-get install rabbitvcs-gedit
$ sudo apt-get install rabbitvcs-cli

I had to do the following, as RabbitVCS menu entries were not showing up in the Nautilus:

$ sudo chown -R $USER:$USER ~/.config/rabbitvcs

Courtesy: http://aruizca.com/how-to-integrate-rabbitvcs-with-nautilus-file-manager-in-ubuntu-14-04-trusty-tahr/

After running the above command, the menu entries are visible.