added UserTests.cs and User.cs; functionalities to follow
added CRUD operation tests to user (no db implementation)
added CRUD operation tests to User (no db implementation)
added CRUD operation tests to user (no db implementation)

added CRUD operation tests to User (no db implementation)
refactored method names and rebased merges
fix conflicts
fixed merge conflicts with upstream (card label updates)
Merge remote-tracking branch 'upstream/master'
Merge pull request #112 from mejas/master

add user core