'rvm gemset list' now has a '=>' for the currently used gemset

https://www.pivotaltracker.com/story/show/10325081

scripts/gemsets

@@ -225,10 +225,21 @@ gemset_list()
 
     if [[ -n "${rvm_ruby_string:-""}" ]] ; then
 
-      ls "${rvm_gems_path:-"$rvm_path/gems"}/" \
-        | awk -F"${rvm_gemset_separator:-"@"}" \
-        "/${rvm_ruby_string}${rvm_gemset_separator:-"@"}/{print \$2}" \
-        2>/dev/null
+      # What's the current gemset?
+      local current_gemset="${GEM_HOME:-}"
+      # We only care about the stuff to the right of the separator.
+      current_gemset="${current_gemset##*${rvm_gemset_separator:-@}}"
+
+      # Figure out the active gemsets for this version.
+      for gemset in "${rvm_gems_path:-${rvm_path}/gems}/${rvm_ruby_string}${rvm_gemset_separator:-@}"*
+      do
+	gemset="${gemset##*${rvm_gemset_separator:-@}}"
+	if [[ "${gemset}" = "${current_gemset}" ]]; then
+	  echo "=> ${gemset}"
+        else
+          echo "   ${gemset}"
+	fi
+      done
 
     else
       rvm_error "\$rvm_ruby_string is not set!"