Complete a TODO in "4. Add auth features.md" (#78)

* Update 4. Add auth features.md

* Update 4. Add auth features.md

* Update 4. Add auth features.md

Author: natemcmaster

docs/4. Add auth features.md

@@ -13,7 +13,19 @@ In this module we're going to add the capability for users to register and sign-
 1. Click the "Add" button
 
 ### Adding Identity via the Command Line
-**TODO**
+1. Open a command line to the **FrontEnd** project folder
+1. If you haven't done this already, install the command-line scaffolding tool.
+   ```
+   dotnet tool install -g dotnet-aspnet-codegenerator
+   ```
+1. Add the Microsoft.VisualStudio.Web.CodeGeneration.Design package to the project.
+   ```
+   dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design --version 2.2.0
+   ```
+1. Run this command to generate the code to use Identity.
+   ```
+   dotnet aspnet-codegenerator identity --dbContext FrontEnd.Data.IdentityDbContext --userClass FrontEnd.Data.User
+   ```
 
 ## Organize the newly created files
 > Note the new files added to the project in the "Areas/Identity" folder. We're going to clean these up a little to better match this project's conventions.
@@ -30,7 +42,7 @@ In this module we're going to add the capability for users to register and sign-
 ## Add the Identity links to the site header
 > The scaffolded out Identity system includes a Razor partial view that contains the Identity-related UI for the site header, e.g. Login and Register links, user name once logged in, etc. We need to add a call to this partial from our site's own layout page:
 
-1. Open the `_Layout.cs` file and find the following line: `<div class="navbar-collapse collapse d-sm-inline-flex flex-sm-row-reverse">`
+1. Open the `_Layout.cshtml` file and find the following line: `<div class="navbar-collapse collapse d-sm-inline-flex flex-sm-row-reverse">`
 1. Immediately after this line, add a call to render the newly added `_LoginPartial.cshtml` using the `<partial />` Tag Helper:
     ``` html
     <div class="navbar-collapse collapse d-sm-inline-flex flex-sm-row-reverse">