MVC 6 was part of ASP.NET 5, but due to some major changes in the code base, they decided to change its name from ASP.NET 5 to ASP.NET Core. You can read about here: http://www.hanselman.com/blog/ASPNET5IsDeadIntroducingASPNETCore10AndNETCore10.aspx
For the Dependency Injection framework to resolve IRepository, it must first be registered with the container. For example, in ConfigureServices, add the following: AddScoped is just one example of a service lifetime: For web applications, a scoped lifetime indicates that services are created once per client request (connection). See the docs for more information on Dependency Injection in ASP.NET Core.
To break down the error message: Unable to resolve service for type ‘WebApplication1.Data.BloggerRepository’ while attempting to activate ‘WebApplication1.Controllers.BlogController’. That is saying that your application is trying to create an instance of BlogController but it doesn’t know how to create an instance of BloggerRepository to pass into the constructor. Now look at your startup: That is saying whenever a IBloggerRepository is required, create a BloggerRepository and … Read more