add gitignore and fix imports

.gitignore

@@ -0,0 +1,6 @@
+*.pyc
+.DS_Store
+backup
+chroma
+.ipynb_checkpoints
+*/.ipynb_checkpoints/*

populate_database.py

@@ -1,14 +1,15 @@
 import argparse
 import os
 import shutil
-from langchain.document_loaders.pdf import PyPDFDirectoryLoader
+from langchain_community.document_loaders.pdf import PyPDFDirectoryLoader
 from langchain_text_splitters import RecursiveCharacterTextSplitter
 from langchain.schema.document import Document
 from get_embedding_function import get_embedding_function
 from langchain_community.vectorstores.chroma import Chroma
 
 import warnings
-warnings.filterwarnings("ignore", category=DeprecationWarning) 
+
+warnings.filterwarnings("ignore", category=DeprecationWarning)
 
 CHROMA_PATH = "chroma"
 DATA_PATH = "data"