Changed solution.
Merge branch 'Slava' of https://github.com/VadzimBura/GroupProject into Vika

Conflicts:
	FileExchange/FileExchange.v12.suo
Merge branch 'Slava' of https://github.com/VadzimBura/GroupProject into Vika

Conflicts:
	FileExchange/FileExchange.v12.suo
Add foreign key attributes to dal entities, enable migrations.
Merge pull request #1 from VadzimBura/Vadzim

Add foreign key attributes to dal entities, enable migrations.
Merge pull request #1 from VadzimBura/Vadzim

Add foreign key attributes to dal entities, enable migrations.
Merge branch 'master' of https://github.com/VadzimBura/GroupProject
Merge branch 'Vadzim' into Slava

Conflicts:
	FileExchange/FileExchange.BLL/FileExchange.BLL.csproj
	FileExchange/FileExchange.Common/IoC.cs
	FileExchange/FileExchange.DAL/Entities/Comment.cs
	FileExchange/FileExchange.DAL/Entities/File.cs
	FileExchange/FileExchange.DAL/Entities/News.cs
	FileExchange/FileExchange.DAL/Entities/Tag.cs
	FileExchange/FileExchange.DAL/Entities/User.cs
Merge?
Merge branch 'Slava'
Merge with Slava branch
Rename viewmodels, create directories for viewmodels.
Add user and role managers, email and sms services (not implemented yet).
Add UserManager and RoleManager to IUnitOfWork.
Add IdentityExtensions, Startup.Auth file.
Add NotNullOrEmptyAttribute and ValidatationInterceptor.
Add not null check to repository methods
Add GenerateIdentity method to User entity
Add IoC container.
Add AuthorizationService and actions for AuthorizationController