,--------.       
      |User    |       
      |--------|       
      |email   |       
      |name    |       
      |password|       
      `--------'       
           |           
           |           
       ,------.        
       |Client|        
       |------|        
       |name  |        
       `------'        
                       
            ,---------.
 ,-------.  |TimeBlock|
 |Project|  |---------|
 |-------|  |duration |
 |name   |  |billable |
 `-------'  |[paid]   |
     |      `---------'
     |            |    
                  |    
,---------.  ,-------. 
|TimeEntry|  |Invoice| 
|---------|  |-------| 
|started  |  |[id]   | 
|[stopped]|  |[link] | 
|title    |  `-------' 
`---------'