use gemset in rvmrc (thanks bowsersenior) - closes #231

.rvmrc

@@ -1 +1,23 @@
-rvm use 1.8.7
+#!/usr/bin/env bash
+
+# adapted from: http://rvm.beginrescueend.com/workflow/rvmrc/
+
+ruby_string="1.8.7"
+gemset_name="cancan"
+
+if rvm list strings | grep -q "${ruby_string}" ; then
+
+  # Load or create the specified environment
+  if [[ -d "${rvm_path:-$HOME/.rvm}/environments" \
+    && -s "${rvm_path:-$HOME/.rvm}/environments/${ruby_string}@${gemset_name}" ]] ; then
+    \. "${rvm_path:-$HOME/.rvm}/environments/${ruby_string}@${gemset_name}"
+  else
+    rvm --create  "${ruby_string}@${gemset_name}"
+  fi
+
+else
+
+  # Notify the user to install the desired interpreter before proceeding.
+  echo "${ruby_string} was not found, please run 'rvm install ${ruby_string}' and then cd back into the project directory."
+
+fi