chore: Add TripViewSet and TripSerializer for managing trips

backend/server/adventures/permissions.py

@@ -0,0 +1,15 @@
+from rest_framework import permissions
+
+class IsOwnerOrReadOnly(permissions.BasePermission):
+    """
+    Custom permission to only allow owners of an object to edit it.
+    """
+
+    def has_object_permission(self, request, view, obj):
+        # Read permissions are allowed to any request,
+        # so we'll always allow GET, HEAD or OPTIONS requests.
+        if request.method in permissions.SAFE_METHODS:
+            return True
+
+        # Write permissions are only allowed to the owner of the object.
+        return obj.user_id == request.user