CheckHashPassword: hash for password to bool.

ClearSession: delete session from User.

GetAdmin: allows access only to authenticated administrators.

GetAuth: get session to authenticated.

GetFlash: get session for flash messages.

GetFlashError: get session for flash message: []error.

GetFlashSuccess: get session for flash messages: []success.

IsAdmin: allows access only to authenticated administrators.

IsUser: allows access only to authenticated users.

PasswordHash: hash for password to string.

RefreshSession: refresh session from User.

SetFlash: set session for flash message.

SetFlashError: get session for flash message: error.

SetFlashSuccess: set session for flash message: success.

SetSession: set session from User.