I have created a function app deployment slot. I have published from Visual Studio and it says your Function app is ready.
But when I go to the Function app slot I cant see any functions, it says

  We were not able to load some functions in the list due to errors. Refresh the page to 
 try again
  Encountered an error (InternalServerError) from host runtime.

and on the top of the page it says :

  microsoft.azure.webjobs.extensions.durabletask: Task Hub name must be specified in 
  host.json when using slots. Specified name must not equal the default HubName 
  (funcapp1).

Is the host.json in my app or do I need to do it on Azure ?
Also can i give it any name or do I need to create a Hub ?