move initmime from beego.Run to hookfunc

@@ -18,6 +18,8 @@ var hooks []hookfunc       //hook function slice to store the hookfunc
 
 func init() {
 	hooks = make([]hookfunc, 0)
+	//init mime
+	AddAPPStartHook(initMime)
 }
 
 // Router adds a patterned controller handler to BeeApp.
@@ -112,9 +114,6 @@ func Run() {
 		}
 	}
 
-	//init mime
-	initMime()
-
 	// do hooks function
 	for _, hk := range hooks {
 		err := hk()

@@ -544,8 +544,9 @@ var mimemaps map[string]string = map[string]string{
 	".mustache":    "text/html",
 }
 
-func initMime() {
+func initMime() error {
 	for k, v := range mimemaps {
 		mime.AddExtensionType(k, v)
 	}
+	return nil
 }