DIG RUBY

I think you already heard of RVM, a great tool for ruby version management.

What I like most is Gemset, It allow you manage you gems in separate namespace.

First, Install RVM. The official website have great document

Then Install ruby, I’ll install ruby 1.8.7

After you installed ruby, you will have default gemset and global gemset
List all you gemset

Create new gemset

Use your newly created gemset

You can also set your newly created gemset as default

Here you may ask, do I need install all basic gem like ruby-debug for every gemset?

RVM has already solved your problem.

First, switch to your global gemset.

Then Install gems which you think it is default gem

Then, you can switch back to your gemset.

You may think, I may installed some gems twice, here you can uninstall the gem you have already installed in global gemset.