I have geckodriver installed in my development directory
ls | grep geckodriver
geckodriver
geckodriver-v0.11.1-linux64.tar.gz
I also exported
You have selenium-webdriver-3.0.0.beta3.1
which is only for Firefox 48 and later (and not yet properly working). Fallback to selenium-webdriver
version 2.53.4
and try again.
And also try this..
gem uninstall selenium-webdriver
gem install selenium-webdriver -v 2.53.4