Fix #231 (#232)

Make sure middleware is Any[] before adding ReviseMiddleware

src/core.jl

@@ -132,6 +132,7 @@ function serve(ctx::Context;
         if ctx.mod === nothing
             @warn "You are trying to use the `revise` option without @oxidise. Code in the `Main` module, which likely includes your routes, will not be tracked and revised."
         end
+        middleware = convert(Vector{Any}, middleware)
         insert!(middleware, 1, ReviseHandler(ctx))
     end