feat: implement blog project with CI pipeline

app/core/exceptions.py

@@ -0,0 +1,25 @@
+class AppException(Exception):
+    def __init__(self, message: str, status_code: int = 500):
+        self.message = message
+        self.status_code = status_code
+        super().__init__(self.message)
+
+
+class NotFoundError(AppException):
+    def __init__(self, message: str = "Resource not found"):
+        super().__init__(message, status_code=404)
+
+
+class ValidationError(AppException):
+    def __init__(self, message: str = "Validation failed"):
+        super().__init__(message, status_code=400)
+
+
+class UnauthorizedError(AppException):
+    def __init__(self, message: str = "Unauthorized"):
+        super().__init__(message, status_code=401)
+
+
+class ForbiddenError(AppException):
+    def __init__(self, message: str = "Forbidden"):
+        super().__init__(message, status_code=403)