Fix travis error (rack)

.travis.yml

@@ -5,9 +5,9 @@ sudo: false
 #
 
 rvm:
-  - &ruby1 2.3.0
-  - &ruby2 2.2.4
-  - &ruby3 2.1.8
+  - &ruby23 2.3.1
+  - &ruby22 2.2.4
+  - &ruby21 2.1.8
   - &rhead ruby-head
 
 #

Gemfile

@@ -5,4 +5,9 @@ group :test do
   gem "rake"
 end
 
-gem "jekyll-assets", "~> 2.2", :require => false
+gem "jekyll-assets", "~> 2.2", :require => false
+
+# Fix for travis
+if (Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.2.2'))
+  gem "rack", "< 2" 
+end

jekyll-pdf.gemspec

@@ -13,10 +13,10 @@ Gem::Specification.new do |spec|
     A Jekyll plugin, that allows you to create PDF versions of your pages & documents.
   DESC
 
-  spec.add_runtime_dependency("wkhtmltopdf-installer", "~> 0.12")
-  spec.add_runtime_dependency("pdfkit", "~> 0.8")
-  spec.add_runtime_dependency("digest", "~> 0")
-  spec.add_runtime_dependency("jekyll", ">= 2.0", "~> 3.1")
+  spec.add_runtime_dependency "wkhtmltopdf-installer", "~> 0.12"
+  spec.add_runtime_dependency "pdfkit", "~> 0.8"
+  spec.add_runtime_dependency "digest", "~> 0"
+  spec.add_runtime_dependency "jekyll", ">= 2.0", "~> 3.1"
 
   spec.add_development_dependency "bundler", "~> 1.6"
 end