Add gem hook

scripts/override_gem

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+if [[ -z "$rvm_leave_gem_alone" ]]; then
+  gem() {
+    command gem "$@"
+    local gem_result="$?"
+    hash -r
+    return $gem_result
+  }
+fi

scripts/rvm

@@ -61,6 +61,7 @@ if [[ "$rvm_loaded_flag" != "1" ]] || [[ "$rvm_reload_flag" = "1" ]] ; then
     source "$rvm_scripts_path/cli"
     source "$rvm_scripts_path/manpages"
     source "$rvm_scripts_path/cd"
+    source "$rvm_scripts_path/override_gem"
 
     rvm_loaded_flag=1