Improve appraisal setup

Test against:

* Rails 4.2 legacy setup
* Rails 5.1, Active Admin 1.x
* Rails 5.x, Active Admin 1.x

Author: tf

.travis.yml

@@ -10,7 +10,7 @@ cache:
 
 gemfile:
   - gemfiles/rails_4.2_active_admin_1.0.0.pre4.gemfile
-  - gemfiles/rails_5.1_active_admin_1.0.gemfile
-  - gemfiles/rails_5.1_active_admin_1.1.gemfile
+  - gemfiles/rails_5.1_active_admin_1.x.gemfile
+  - gemfiles/rails_5.x_active_admin_1.x.gemfile
 
 script: bundle exec rspec

Appraisals

@@ -4,12 +4,12 @@ appraise 'rails-4.2-active-admin-1.0.0.pre4' do
   gem 'jquery-ui-rails', '~> 5.0'
 end
 
-appraise 'rails-5.1-active-admin-1.0' do
-  gem 'rails', '~> 5.1'
+appraise 'rails-5.1-active-admin-1.x' do
+  gem 'rails', '~> 5.1.0'
   gem 'activeadmin', '~> 1.0'
 end
 
-appraise 'rails-5.1-active-admin-1.1' do
-  gem 'rails', '~> 5.1'
-  gem 'activeadmin', '~> 1.1'
+appraise 'rails-5.x-active-admin-1.x' do
+  gem 'rails', '~> 5.2'
+  gem 'activeadmin', '~> 1.0'
 end

gemfiles/rails_5.1_active_admin_1.1.gemfile renamed to gemfiles/rails_5.1_active_admin_1.x.gemfile

@@ -3,7 +3,7 @@
 source "https://rubygems.org"
 
 gem "sass-rails"
-gem "rails", "~> 5.1"
-gem "activeadmin", "~> 1.1"
+gem "rails", "~> 5.1.0"
+gem "activeadmin", "~> 1.0"
 
 gemspec path: "../"

gemfiles/rails_5.1_active_admin_1.0.gemfile renamed to gemfiles/rails_5.x_active_admin_1.x.gemfile

@@ -3,7 +3,7 @@
 source "https://rubygems.org"
 
 gem "sass-rails"
-gem "rails", "~> 5.1"
+gem "rails", "~> 5.2"
 gem "activeadmin", "~> 1.0"
 
 gemspec path: "../"