Remove redundant step to add the UploadConference method (#76)

Author: AndriySvyryd

docs/2. Build out BackEnd and Refactor.md

@@ -688,24 +688,6 @@ Okay, now we need to update our `ApplicationDbContext` so Entity Framework knows
 1. Copy the `DataLoader.cs` class from [here](/src/BackEnd/Data/DataLoader.cs) into the `Data` directory of the `BackEnd` project.
 1. Copy the `SessionizeLoader.cs` and `DevIntersectionLoader.cs` classes from [here](/src/BackEnd/Data/) into the current project's `/src/BackEnd/Data/` directory. 
  > Note: We have data loaders from the two conference series where this workshop has been presented most; you can update this to plug in your own conference file format.
-1. Add the following method to the `ConferencesController`:
-   ```csharp
-   [HttpPost("upload")]
-   [Consumes("multipart/form-data")]
-   public async Task<IActionResult> UploadConference([Required, FromForm]string conferenceName, IFormFile file)
-   {
-       var loader = new SessionizeLoader();
-
-       using (var stream = file.OpenReadStream())
-       {
-           await loader.LoadDataAsync(conferenceName, stream, _db);
-       }
-
-       await _db.SaveChangesAsync();
-
-       return Ok();
-   }
-   ```
 1. Run the application to see the updated data via Swagger UI.
 1. Use the Swagger UI to upload [NDC_London_2019.json](/src/BackEnd/Data/Import/NDC_London_2019.json) to the `/api/Conferences/upload` API.