Use head version of all released MRI versions

.travis.yml

@@ -7,11 +7,10 @@ script: bundle exec rake travis
 matrix:
   fast_finish: true
   include:
-    - rvm: 1.9.3
-    - rvm: 2.0.0
-    - rvm: 2.1.0
-    - rvm: 2.1.5
-    - rvm: 2.1.5
+    - rvm: 2.0
+    - rvm: 2.1
+    - rvm: 2.2
+    - rvm: 2.2
       gemfile: gemfiles/Gemfile-edge
     - rvm: jruby-19mode
     - rvm: jruby-head

fog.gemspec

@@ -45,7 +45,7 @@ Gem::Specification.new do |s|
   s.extra_rdoc_files = %w[README.md]
 
   ## Ruby version
-  s.required_ruby_version = ">= 1.9.3"
+  s.required_ruby_version = ">= 2"
 
   ## List your runtime dependencies here. Runtime dependencies are those
   ## that are needed for an end user to actually USE your code.