Update gemspec to also support Rails 3.2

Author: reidmorrison

lib/rails_semantic_logger/version.rb

@@ -1,3 +1,3 @@
 module RailsSemanticLogger #:nodoc
-  VERSION = '4.1.3'
+  VERSION = '4.2.0'
 end

rails_semantic_logger.gemspec

@@ -17,6 +17,6 @@ Gem::Specification.new do |spec|
   spec.license               = 'Apache-2.0'
   spec.has_rdoc              = true
   spec.required_ruby_version = '>= 2.1'
-  spec.add_dependency 'rails', '>= 4.0'
+  spec.add_dependency 'rails', '>= 3.2'
   spec.add_dependency 'semantic_logger', '~> 4.1'
 end