Fix test db

Blog.DAL.Tests/RepositoryTests.cs

@@ -21,6 +21,10 @@ namespace Blog.DAL.Tests
             var context = new BlogContext();
             context.Database.CreateIfNotExists();
             var repository = new BlogRepository();
+            // -- prepare data in db
+            context.Posts.ToList().ForEach(x => context.Posts.Remove(x));
+            context.Posts.Add(new Post { Author = "test", Content = "test, test, test..." });
+            context.SaveChanges();
             // act
             var result = repository.GetAllPosts();
             // assert