Require ruby version 2.0 or better

Author: flori

Rakefile

@@ -95,6 +95,7 @@ if defined?(Gem) and defined?(Gem::PackageTask)
     s.email = "flori@ping.de"
     s.homepage = "http://flori.github.com/#{PKG_NAME}"
     s.license = 'Ruby'
+    s.required_ruby_version = '~>2.0'
   end
 
   desc 'Creates a json_pure.gemspec file'
@@ -132,6 +133,7 @@ if defined?(Gem) and defined?(Gem::PackageTask)
     s.email = "flori@ping.de"
     s.homepage = "http://flori.github.com/#{PKG_NAME}"
     s.license = 'Ruby'
+    s.required_ruby_version = '~>2.0'
   end
 
   desc 'Creates a json.gemspec file'

json.gemspec

@@ -16,6 +16,7 @@ Gem::Specification.new do |s|
   s.homepage = "http://flori.github.com/json".freeze
   s.licenses = ["Ruby".freeze]
   s.rdoc_options = ["--title".freeze, "JSON implemention for ruby".freeze, "--main".freeze, "README.md".freeze]
+  s.required_ruby_version = Gem::Requirement.new("~> 2.0".freeze)
   s.rubygems_version = "2.6.8".freeze
   s.summary = "JSON Implementation for Ruby".freeze
   s.test_files = ["./tests/test_json.rb".freeze, "./tests/test_json_addition.rb".freeze, "./tests/test_json_encoding.rb".freeze, "./tests/test_json_fixtures.rb".freeze, "./tests/test_json_generate.rb".freeze, "./tests/test_json_generic_object.rb".freeze, "./tests/test_json_string_matching.rb".freeze, "./tests/test_json_unicode.rb".freeze]