requiring redis and memcache-client in gemspec for now

trebuchet.gemspec

@@ -17,8 +17,10 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ["lib"]
 
-  # redis and memcache are optional
   s.add_dependency 'json'
+  # FIXME: make redis and memcache optional by moving them into separate support gems
+  s.add_dependency 'redis'
+  s.add_dependency 'memcache-client'
 
   if s.respond_to? :specification_version then
     s.specification_version = 3