Fixed selenium gem version to make ci tests working again.

Gemfile

@@ -107,7 +107,7 @@ group :development, :test do
   gem 'coveralls',         require: false
 
   # UI tests w/ Selenium
-  gem 'selenium-webdriver'
+  gem 'selenium-webdriver', '2.53.4'
 
   # livereload on template changes (html, js, css)
   gem 'guard',             require: false

Gemfile.lock

@@ -378,6 +378,7 @@ GEM
     selenium-webdriver (2.53.4)
       childprocess (~> 0.5)
       rubyzip (~> 1.0)
+      websocket (~> 1.0)
     shellany (0.0.1)
     simple-rss (1.3.1)
     simple_oauth (0.3.1)
@@ -448,6 +449,7 @@ GEM
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
       hashdiff
+    websocket (1.2.4)
     websocket-driver (0.6.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.2)
@@ -521,7 +523,7 @@ DEPENDENCIES
   rubocop
   rubyntlm!
   sass-rails
-  selenium-webdriver
+  selenium-webdriver (= 2.53.4)
   simple-rss
   simplecov
   simplecov-rcov