Add rails-6 to build matrix

.travis.yml

@@ -1,14 +1,28 @@
 language: ruby
 cache: bundler
 rvm:
-  - 2.5
-  - 2.4
-  - 2.3
+- 2.5
+- 2.4
 gemfile:
-  - gemfiles/rails_52.gemfile
-  - gemfiles/rails_51.gemfile
-  - gemfiles/rails_50.gemfile
-  - gemfiles/rails_42.gemfile
+- gemfiles/rails_52.gemfile
+- gemfiles/rails_51.gemfile
+matrix:
+  include:
+  # old rails
+  - rvm: 2.5
+    gemfile: gemfiles/rails_50.gemfile
+  - rvm: 2.5
+    gemfile: gemfiles/rails_42.gemfile
+  # old rubies
+  - rvm: 2.3
+    gemfile: gemfiles/rails_52.gemfile
+  # future rails
+  - rvm: 2.5
+    gemfile: gemfiles/rails_60.gemfile
+  # Allow rails 6 to fail while master branch is used
+  allow_failures:
+  - rvm: 2.5
+    gemfile: gemfiles/rails_60.gemfile
 notifications:
   email: false
 

Appraisals

@@ -1,3 +1,10 @@
+appraise 'rails-60' do
+  git 'https://github.com/rails/rails.git' do
+    gem 'actionpack', '~> 6.0.0.alpha'
+    gem 'railties', '~> 6.0.0.alpha'
+  end
+end
+
 appraise 'rails-52' do
   gem 'actionpack', '~> 5.2.0.beta2'
   gem 'railties', '~> 5.2.0.beta2'

gemfiles/rails_60.gemfile

@@ -0,0 +1,23 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+git "https://github.com/rails/rails.git" do
+  gem "actionpack", "~> 6.0.0.alpha"
+  gem "railties", "~> 6.0.0.alpha"
+end
+
+group :development do
+  gem "appraisal", "~> 2.2"
+  gem "pry", "~> 0.10.1"
+  gem "pry-byebug", "~> 3.2.0"
+  gem "sdoc", "~> 0.4.1"
+  gem "telegram-bot-types", "~> 0.3.0"
+  gem "rspec", "~> 3.5.0"
+  gem "rspec-its", "~> 1.1.0"
+  gem "rspec-rails", "~> 3.5.0"
+  gem "rubocop", "~> 0.52.1"
+  gem "coveralls", "~> 0.8.2", require: false
+end
+
+gemspec path: "../"