Added session first implementation:

+ Added session in the database and added session controller
+ Added session in authorize attribute/Login
+ Added Logout function
* Refactor database models

Step.Model/DatabaseModels/UserModel.cs

@@ -10,7 +10,7 @@ using System.Threading.Tasks;
 
 namespace Step.Model.DatabaseModels
 {
-    [Table("users")]
+    [Table("user")]
     public class UserModel
     {
         [Key]