fix serval bugs on sidebar.

app/models/module_app.rb

@@ -63,11 +63,31 @@ class ModuleApp
   end
 
   def is_manager?(user)
-    managing_users.include?(user)
+    if user.nil?
+      return false
+    else
+      m_users = managing_users
+      if m_users.blank?
+        false
+      else
+        m_users.include?(user)  
+      end
+    end
   end
   
   def is_sub_manager?(user)
-    sub_managing_users.include?(user) || is_manager?(user)
+    if user.nil?
+      return false
+    else # when user is guest
+      s_m_users = sub_managing_users
+      result = false
+      if s_m_users.blank?
+        result = false
+      else
+        result = s_m_users.include?(user) 
+      end
+      result || is_manager?(user)
+    end
   end
   
   def managing_users