class Mustache::ContextMiss
A ContextMiss is raised whenever a tag's target can not be found in the current context if `Mustache#raise_on_context_miss?` is set to true.
For example, if your View class does not respond to `music` but your template contains a `{{music}}` tag this exception will be raised.
By default it is not raised. See Mustache.raise_on_context_miss.