For example:

```ruby
module Conjur
  class Environment < RestClient::Resource
    include ActsAsAsset
    
    def add_variable(name, variableid)
      log do |logger|
        logger << "Adding variable #{name} = #{variableid} to environment #{id}"
      end
      invalidate do
        RestClient::Resource.new(self['variables'].url, options).post(name: name, variableid: variableid) 
      end
    end
end
```