Updated gemspec to support rack 2

The code seems to work with rack 2 without any modifications. However,
to make sure that both rack 1 and rack 2 compatibility is maintained,
I've added Appraisal, which makes it easier to test against multiple
versions of rack. The default test task will now test against rack
1.5, 1.6 and 2.0.

Appraisals

@@ -0,0 +1,11 @@
+appraise "rack-1-5" do
+  gem "rack", "~> 1.5"
+end
+
+appraise "rack-1-6" do
+  gem "rack", "~> 1.6"
+end
+
+appraise "rack-2-0" do
+  gem "rack", "~> 2.0"
+end

Rakefile

@@ -1,7 +1,13 @@
 require 'rake/testtask'
 
 
-task :default => :test
+if ENV["APPRAISAL_INITIALIZED"]
+  task :default => :test
+else
+  require 'appraisal'
+
+  task :default => :appraisal
+end
 
 Rake::TestTask.new do |t|
   t.pattern = 'test/test_*.rb'

gemfiles/rack_1.gemfile

@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org/"
+
+gem "appraisal"
+gem "rack", "< 2"
+
+group :test do
+  gem "cucumber", "2.1.0"
+end
+
+gemspec :path => "../"

gemfiles/rack_1.gemfile.lock

@@ -0,0 +1,82 @@
+PATH
+  remote: ..
+  specs:
+    rack-jekyll (0.5.0)
+      jekyll (>= 1.3)
+      listen (>= 1.3)
+      rack (>= 1.5)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.5.0)
+      public_suffix (~> 2.0, >= 2.0.2)
+    appraisal (2.1.0)
+      bundler
+      rake
+      thor (>= 0.14.0)
+    builder (3.2.3)
+    colorator (1.1.0)
+    cucumber (2.1.0)
+      builder (>= 2.1.2)
+      cucumber-core (~> 1.3.0)
+      diff-lcs (>= 1.1.3)
+      gherkin3 (~> 3.1.0)
+      multi_json (>= 1.7.5, < 2.0)
+      multi_test (>= 0.1.2)
+    cucumber-core (1.3.1)
+      gherkin3 (~> 3.1.0)
+    diff-lcs (1.3)
+    ffi (1.9.18)
+    forwardable-extended (2.6.0)
+    gherkin3 (3.1.2)
+    jekyll (3.4.2)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      jekyll-sass-converter (~> 1.0)
+      jekyll-watch (~> 1.1)
+      kramdown (~> 1.3)
+      liquid (~> 3.0)
+      mercenary (~> 0.3.3)
+      pathutil (~> 0.9)
+      rouge (~> 1.7)
+      safe_yaml (~> 1.0)
+    jekyll-sass-converter (1.5.0)
+      sass (~> 3.4)
+    jekyll-watch (1.5.0)
+      listen (~> 3.0, < 3.1)
+    kramdown (1.13.2)
+    liquid (3.0.6)
+    listen (3.0.8)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+    mercenary (0.3.6)
+    minitest (5.10.1)
+    multi_json (1.12.1)
+    multi_test (0.1.2)
+    pathutil (0.14.0)
+      forwardable-extended (~> 2.6)
+    public_suffix (2.0.5)
+    rack (1.6.5)
+    rake (12.0.0)
+    rb-fsevent (0.9.8)
+    rb-inotify (0.9.8)
+      ffi (>= 0.5.0)
+    rouge (1.11.1)
+    safe_yaml (1.0.4)
+    sass (3.4.23)
+    thor (0.19.4)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  appraisal
+  cucumber (= 2.1.0)
+  minitest
+  rack (< 2)
+  rack-jekyll!
+  rake
+
+BUNDLED WITH
+   1.14.6

gemfiles/rack_1_5.gemfile

@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org/"
+
+gem "appraisal"
+gem "rack", "~> 1.5"
+
+group :test do
+  gem "cucumber", "2.1.0"
+end
+
+gemspec :path => "../"

gemfiles/rack_1_5.gemfile.lock

@@ -0,0 +1,82 @@
+PATH
+  remote: ..
+  specs:
+    rack-jekyll (0.5.0)
+      jekyll (>= 1.3)
+      listen (>= 1.3)
+      rack (>= 1.5)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.5.0)
+      public_suffix (~> 2.0, >= 2.0.2)
+    appraisal (2.1.0)
+      bundler
+      rake
+      thor (>= 0.14.0)
+    builder (3.2.3)
+    colorator (1.1.0)
+    cucumber (2.1.0)
+      builder (>= 2.1.2)
+      cucumber-core (~> 1.3.0)
+      diff-lcs (>= 1.1.3)
+      gherkin3 (~> 3.1.0)
+      multi_json (>= 1.7.5, < 2.0)
+      multi_test (>= 0.1.2)
+    cucumber-core (1.3.1)
+      gherkin3 (~> 3.1.0)
+    diff-lcs (1.3)
+    ffi (1.9.18)
+    forwardable-extended (2.6.0)
+    gherkin3 (3.1.2)
+    jekyll (3.4.2)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      jekyll-sass-converter (~> 1.0)
+      jekyll-watch (~> 1.1)
+      kramdown (~> 1.3)
+      liquid (~> 3.0)
+      mercenary (~> 0.3.3)
+      pathutil (~> 0.9)
+      rouge (~> 1.7)
+      safe_yaml (~> 1.0)
+    jekyll-sass-converter (1.5.0)
+      sass (~> 3.4)
+    jekyll-watch (1.5.0)
+      listen (~> 3.0, < 3.1)
+    kramdown (1.13.2)
+    liquid (3.0.6)
+    listen (3.0.8)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+    mercenary (0.3.6)
+    minitest (5.10.1)
+    multi_json (1.12.1)
+    multi_test (0.1.2)
+    pathutil (0.14.0)
+      forwardable-extended (~> 2.6)
+    public_suffix (2.0.5)
+    rack (1.6.5)
+    rake (12.0.0)
+    rb-fsevent (0.9.8)
+    rb-inotify (0.9.8)
+      ffi (>= 0.5.0)
+    rouge (1.11.1)
+    safe_yaml (1.0.4)
+    sass (3.4.23)
+    thor (0.19.4)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  appraisal
+  cucumber (= 2.1.0)
+  minitest
+  rack (~> 1.5)
+  rack-jekyll!
+  rake
+
+BUNDLED WITH
+   1.14.6

gemfiles/rack_1_6.gemfile

@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org/"
+
+gem "appraisal"
+gem "rack", "~> 1.6"
+
+group :test do
+  gem "cucumber", "2.1.0"
+end
+
+gemspec :path => "../"

gemfiles/rack_1_6.gemfile.lock

@@ -0,0 +1,82 @@
+PATH
+  remote: ..
+  specs:
+    rack-jekyll (0.5.0)
+      jekyll (>= 1.3)
+      listen (>= 1.3)
+      rack (>= 1.5)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.5.0)
+      public_suffix (~> 2.0, >= 2.0.2)
+    appraisal (2.1.0)
+      bundler
+      rake
+      thor (>= 0.14.0)
+    builder (3.2.3)
+    colorator (1.1.0)
+    cucumber (2.1.0)
+      builder (>= 2.1.2)
+      cucumber-core (~> 1.3.0)
+      diff-lcs (>= 1.1.3)
+      gherkin3 (~> 3.1.0)
+      multi_json (>= 1.7.5, < 2.0)
+      multi_test (>= 0.1.2)
+    cucumber-core (1.3.1)
+      gherkin3 (~> 3.1.0)
+    diff-lcs (1.3)
+    ffi (1.9.18)
+    forwardable-extended (2.6.0)
+    gherkin3 (3.1.2)
+    jekyll (3.4.2)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      jekyll-sass-converter (~> 1.0)
+      jekyll-watch (~> 1.1)
+      kramdown (~> 1.3)
+      liquid (~> 3.0)
+      mercenary (~> 0.3.3)
+      pathutil (~> 0.9)
+      rouge (~> 1.7)
+      safe_yaml (~> 1.0)
+    jekyll-sass-converter (1.5.0)
+      sass (~> 3.4)
+    jekyll-watch (1.5.0)
+      listen (~> 3.0, < 3.1)
+    kramdown (1.13.2)
+    liquid (3.0.6)
+    listen (3.0.8)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+    mercenary (0.3.6)
+    minitest (5.10.1)
+    multi_json (1.12.1)
+    multi_test (0.1.2)
+    pathutil (0.14.0)
+      forwardable-extended (~> 2.6)
+    public_suffix (2.0.5)
+    rack (1.6.5)
+    rake (12.0.0)
+    rb-fsevent (0.9.8)
+    rb-inotify (0.9.8)
+      ffi (>= 0.5.0)
+    rouge (1.11.1)
+    safe_yaml (1.0.4)
+    sass (3.4.23)
+    thor (0.19.4)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  appraisal
+  cucumber (= 2.1.0)
+  minitest
+  rack (~> 1.6)
+  rack-jekyll!
+  rake
+
+BUNDLED WITH
+   1.14.6

gemfiles/rack_2.gemfile

@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org/"
+
+gem "appraisal"
+gem "rack", ">= 2"
+
+group :test do
+  gem "cucumber", "2.1.0"
+end
+
+gemspec :path => "../"