Add the missing dependency step (#70)

Author: AndriySvyryd

docs/2. Build out BackEnd and Refactor.md

@@ -11,6 +11,7 @@ In this session, we'll add the rest of our models and controllers that expose th
 1. Select *.NET Standard* from the project types on the left and select the *Class Libarary (.NET Standard)* template. Name the project ConferenceDTO and press OK.
 ![](images/create-dto-project.png)
 1. Delete the generated `Class1.cs` file from this new project.
+1. Right-click the 'Dependencies' node under the BackENd project, select "Add Reference..." and put a checkmark near ConferenceDTO.
 
 ### Adding the ConferenceDTO project via the Command Line
 1. Open a command prompt and navigate to the root `ConferencePlanner` directory.