Upgrade Ruby to 2.6.6

Note this version includes the Bundler gem, and so we no longer need to
install it while deploying.

.ruby-version

@@ -1 +1 @@
-2.5.8
+2.6.6

README.md

@@ -39,7 +39,7 @@ You can access the main website of the project at [http://consulproject.org](htt
 
 **NOTE**: For more detailed instructions check the [docs](https://docs.consulproject.org)
 
-Prerequisites: install git, Ruby 2.5.8, `bundler` gem, Node.js and PostgreSQL (>=9.4).
+Prerequisites: install git, Ruby 2.6.6, Node.js and PostgreSQL (>=9.4).
 
 ```bash
 git clone https://github.com/consul/consul.git

README_ES.md

@@ -36,7 +36,7 @@ Puedes acceder a la página principal del proyecto en [http://consulproject.org]
 
 **NOTA**: para unas instrucciones más detalladas consulta la [documentación](https://docs.consulproject.org)
 
-Prerequisitos: tener instalado git, Ruby 2.5.8, la gema `bundler`, Node.js y PostgreSQL (9.4 o superior).
+Prerequisitos: tener instalado git, Ruby 2.6.6, Node.js y PostgreSQL (9.4 o superior).
 
 ```bash
 git clone https://github.com/consul/consul.git

config/deploy.rb

@@ -50,7 +50,6 @@ namespace :deploy do
 
   after :updating, "rvm1:install:rvm"
   after :updating, "rvm1:install:ruby"
-  after :updating, "install_bundler_gem"
 
   after "deploy:migrate", "add_new_settings"
 
@@ -70,14 +69,6 @@ namespace :deploy do
   end
 end
 
-task :install_bundler_gem do
-  on roles(:app) do
-    within release_path do
-      execute :rvm, fetch(:rvm1_ruby_version), "do", "gem install bundler --version 1.17.1"
-    end
-  end
-end
-
 task :refresh_sitemap do
   on roles(:app) do
     within release_path do