Update Part11.md

[ghhv]

the original keywords of the parts changed were invalid on my side.. guessed these changes based on other samples..

also removed duplicated code.

And clarified that Session code goes in Client-side services??

My first ever pull request! ;-)

[ghhv]

Also, you are not able use to your : DbContextBase in conjunction with with AspNet Identity e.g. : ApiAuthorizationDbContext<ApplicationUser>

[alexyakunin]

Hi, I'll partially accept this PR, coz the configuration logic there is outdated - thanks!