Feat/serialize deserialize (#508)

Co-authored-by: Taranjeet Singh <reachtotj@gmail.com>

embedchain/loaders/pdf_file.py

@@ -1,9 +1,11 @@
 from langchain.document_loaders import PyPDFLoader
 
+from embedchain.helper_classes.json_serializable import register_deserializable
 from embedchain.loaders.base_loader import BaseLoader
 from embedchain.utils import clean_string
 
 
+@register_deserializable
 class PdfFileLoader(BaseLoader):
     def load_data(self, url):
         """Load data from a PDF file."""