Added Each to apply a function for every registered subapplication.

api.go

@@ -14,6 +14,7 @@ import (
 type Application interface {
 	AttachApplication(Application)
 	DestroyApplication(Application)
+	Each(func(Application))
 	Application() *application
 	LoadSession()
 	BindGroup(path string) *RouterGroup

application.go

@@ -165,6 +165,14 @@ func (a *application) DestroyApplication(app Application) {
 	}
 }
 
+// Each applies the function fn for every subapplication currently registered
+// with Capstan.
+func (a *application) Each(fn func(Application)) {
+	for _, subapp := range a.subapps {
+		fn(subapp)
+	}
+}
+
 func (a *application) Application() *application {
 	return a
 }