f.label should work for targeting f.radio_button

It's impossible to automatically generate a label for a radio button using a form helper. The for="" attribute of a label tag cannot be generated with the same ID of a radio button:

• Radio button ID looks like "model_attribute_value1"
• Label for attribute looks like "model_attribute"

I suggest that the "label" method take an optional value attribute like so:

• f.radio_button :attribute, "value1"
• f.label :attribute, "Select value1", :value => "value1"

Additionally, the code should be refactored so that the code which generates the ID "model_attribute_value1" is only in one place and is consistent.