osx does not support version sorting, thanks god for ruby

scripts/rubygems

@@ -50,12 +50,14 @@ can_switch_rubygems()
 
 rubygems_version_list()
 {
-  curl -s https://api.github.com/repos/rubygems/rubygems/tags | sed -n '/"name": / {s/^.*".*": "\(.*\)".*$/\1/; p}' | sort -V
+  curl -s https://api.github.com/repos/rubygems/rubygems/tags |
+    sed -n '/"name": / {s/^.*".*": "v\(.*\)".*$/\1/; p;}' |
+    "${rvm_ruby_binary:-ruby}" -e 'arr=[]; while a=gets() do arr<<a; end; puts arr.map{|a| a.split(/\./).map(&:to_i) }.sort.map{|a| a * "."};'
 }
 
 rubygems_master_sha()
 {
-  curl -s "https://api.github.com/repos/rubygems/rubygems/commits?page=last&per_page=1" | sed -n '/^    "sha":/ {s/^.*".*": "\(.*\)".*$/\1/;p}'
+  curl -s "https://api.github.com/repos/rubygems/rubygems/commits?page=last&per_page=1" | sed -n '/^    "sha":/ {s/^.*".*": "\(.*\)".*$/\1/;p;}'
 }
 
 rubygems_select_version_url()
@@ -88,8 +90,8 @@ rubygems_select_version_url()
   case "$version" in
     latest-*)
       version="${version#latest-}"
-      version="$(rubygems_version_list | grep "^v${version}\." | tail -n 1 )"
-      version="${version#v}"
+      version="$(rubygems_version_list | grep "^${version}\." | tail -n 1 )"
+      version="${version}"
       ;;
   esac