diff --git a/src/code_rag/rag.py b/src/code_rag/rag.py
index 95cbed1..e1fd5f8 100644
--- a/src/code_rag/rag.py
+++ b/src/code_rag/rag.py
@@ -66,7 +66,7 @@ class RAG:
     def create_vector_db(self, extensions=None, force_refresh=False):
         """
         Create or update a vector database, with complete handling of changes.
-        
+
         Args:
             extensions (list[str], optional): List of file extensions to include.
                                            If None, defaults to common programming languages.
@@ -74,18 +74,7 @@ class RAG:
         """
         # Set default extensions for common programming languages if none provided
         if extensions is None:
-            extensions = [
-                # Python
-                '.py', '.pyi', '.pyx',
-                # C/C++
-                '.c', '.cpp', '.cc', '.cxx', '.h', '.hpp', '.hxx',
-                # Rust
-                '.rs',
-                # Documentation
-                '.txt', '.md',
-                # Build/Config
-                '.toml', '.yaml', '.json'
-            ]
+            extensions = default_file_extensions()
         elif isinstance(extensions, str):
             extensions = [extensions]
 
@@ -103,14 +92,12 @@ class RAG:
         if os.path.exists(self.db_dir) and not force_refresh:
             print("Loading existing vector store")
             vectorstore = Chroma(
-                persist_directory=self.db_dir,
-                embedding_function=embeddings
+                persist_directory=self.db_dir, embedding_function=embeddings
             )
         else:
             print("Creating new vector store")
             vectorstore = Chroma(
-                persist_directory=self.db_dir,
-                embedding_function=embeddings
+                persist_directory=self.db_dir, embedding_function=embeddings
             )
 
         # Find all files that match the extensions
@@ -127,14 +114,14 @@ class RAG:
         all_documents = []
         for file_path in all_files:
             try:
-                with open(file_path, 'r', encoding='utf-8') as f:
+                with open(file_path, "r", encoding="utf-8") as f:
                     content = f.read()
                     doc = Document(
                         page_content=content,
                         metadata={
                             "source": os.path.abspath(file_path),
-                            "source_id": os.path.abspath(file_path)
-                        }
+                            "source_id": os.path.abspath(file_path),
+                        },
                     )
                     all_documents.append(doc)
                     print(f"Successfully loaded {file_path}")
@@ -151,9 +138,7 @@ class RAG:
         if force_refresh:
             # Create new vector store from scratch
             vectorstore = Chroma.from_documents(
-                documents=chunks,
-                embedding=embeddings,
-                persist_directory=self.db_dir
+                documents=chunks, embedding=embeddings, persist_directory=self.db_dir
             )
         else:
             # Update existing vector store
@@ -163,7 +148,8 @@ class RAG:
 
             # Find new documents
             new_chunks = [
-                chunk for chunk in chunks
+                chunk
+                for chunk in chunks
                 if chunk.metadata["source"] not in existing_sources
             ]
 
@@ -224,3 +210,136 @@ class RAG:
         """
         response = rag_chain.invoke({"query": query})
         return response["result"]
+
+
+def default_file_extensions():
+    """Return the default file extensions representing common plain text and code files"""
+    return [
+        # Python
+        ".py",
+        ".pyi",
+        ".pyx",
+        ".pyc",
+        ".pyd",
+        ".pyw",
+        # C/C++
+        ".c",
+        ".cpp",
+        ".cc",
+        ".cxx",
+        ".h",
+        ".hpp",
+        ".hxx",
+        ".inc",
+        ".inl",
+        ".ipp",
+        # Rust
+        ".rs",
+        ".rlib",
+        ".rmeta",
+        # Java
+        ".java",
+        ".jsp",
+        ".jav",
+        ".jar",
+        ".class",
+        ".kt",
+        ".kts",
+        ".groovy",
+        # Web
+        ".html",
+        ".htm",
+        ".css",
+        ".scss",
+        ".sass",
+        ".less",
+        ".js",
+        ".jsx",
+        ".ts",
+        ".tsx",
+        ".vue",
+        ".svelte",
+        # Fortran
+        ".f",
+        ".for",
+        ".f90",
+        ".f95",
+        ".f03",
+        ".f08",
+        # Go
+        ".go",
+        ".mod",
+        # Ruby
+        ".rb",
+        ".rbw",
+        ".rake",
+        ".gemspec",
+        # PHP
+        ".php",
+        ".phtml",
+        ".php3",
+        ".php4",
+        ".php5",
+        ".phps",
+        # C#
+        ".cs",
+        ".csx",
+        ".vb",
+        # Swift
+        ".swift",
+        ".swiftmodule",
+        # Shell/Scripts
+        ".sh",
+        ".bash",
+        ".zsh",
+        ".fish",
+        ".ps1",
+        ".bat",
+        ".cmd",
+        # Scala
+        ".scala",
+        ".sc",
+        # Haskell
+        ".hs",
+        ".lhs",
+        ".hsc",
+        # Lua
+        ".lua",
+        ".luac",
+        # R
+        ".r",
+        ".rmd",
+        ".rds",
+        # Perl
+        ".pl",
+        ".pm",
+        ".t",
+        # Documentation
+        ".txt",
+        ".md",
+        ".rst",
+        ".adoc",
+        ".wiki",
+        # Build/Config
+        ".toml",
+        ".yaml",
+        ".yml",
+        ".json",
+        ".xml",
+        ".ini",
+        ".conf",
+        ".cfg",
+        # SQL
+        ".sql",
+        ".mysql",
+        ".pgsql",
+        ".sqlite",
+        # Lisp family
+        ".lisp",
+        ".cl",
+        ".el",
+        ".clj",
+        ".cljc",
+        ".cljs",
+        ".edn",
+    ]