Added a Repository class to help with database code
Added Repository Base Class and Welcome model
Made the methods more succinct
Removed error of id field not set
GetById now returns just one object
Added footer to repository file

Signed-off-by: Enmanuel Toribio <toribiea@gmail.com>
Added comments to the class

Signed-off-by: Enmanuel Toribio <toribiea@gmail.com>
Added documentation

Signed-off-by: Enmanuel Toribio <eats007@gmail.com>