security: Add signing/verification support in transformation

Change-Id: I6364fa0e1ebcc7cc932b401eb50fc56251ea8c84
Refs: #3009
diff --git a/src/security/transform.hpp b/src/security/transform.hpp
index 2d2ef2e..3f83de0 100644
--- a/src/security/transform.hpp
+++ b/src/security/transform.hpp
@@ -36,5 +36,7 @@
 #include "transform/digest-filter.hpp"
 #include "transform/hmac-filter.hpp"
 #include "transform/block-cipher.hpp"
+#include "transform/signer-filter.hpp"
+#include "transform/verifier-filter.hpp"
 
 #endif // NDN_CXX_SECURITY_TRANSFORM_HPP