fixed gemspec in order to test against rails 5.0 and rails 5.1

Author: jonasjabari

matestack-ui-core.gemspec

@@ -17,7 +17,7 @@ Gem::Specification.new do |s|
 
   s.files = Dir["{app,config,db,lib,vendor}/**/*", "LICENSE", "Rakefile", "README.md"]
 
-  s.add_dependency "rails", '>= 5.2'
+  s.add_dependency "rails", '>= 5.0'
   s.add_dependency "haml", '>= 4.1.0.beta.1'
   s.add_dependency "trailblazer-cells", '>= 0.0.3'
   s.add_dependency "cells-rails", '>= 0.1.0'