Allow user to specify BUNDLED_COMMANDS.

bundler-exec.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-BUNDLED_COMMANDS="cucumber heroku rackup rails rake rspec ruby shotgun spec"
+BUNDLED_COMMANDS="${BUNDLED_COMMANDS:-cucumber heroku rackup rails rake rspec ruby shotgun spec}"
 
 ## Functions