I have a model to which I have to record a `PositiveSmallIntegerField` to the object, that is updated daily with the relevant score.

```
class Student(models.Model):
    name = models.CharField(max_length=20)
    grade = models.ForeignKey(Grade)
    rank = ??

```

The number of objects with this model will never exceed 100 and the scores/ranks must be retained for a period of 180 days. The database is Postgresql 9.2.

The rank is calculated daily on the score from another app, which I want to store in the database related to the student model, where I'm stuck with the model design, I have no Idea, what should be done for the ranks? Is there a repeating field in Django? 

Any clues or experiences will be much appreciated

thanks.

### Update:(Adding an example)

The database must look something like this,

```
+---------+-------+----------+----------+----------+----------+----------+----------+
| Student | Grade | 08-01-15 | 08-02-15 | 08-03-15 | 08-04-15 | 08-05-15 | 08-06-15 |
+---------+-------+----------+----------+----------+----------+----------+----------+
| Alex    |     5 |        2 |        1 |        1 |        2 |        3 |        2 |
| John    |     5 |        3 |        2 |        3 |        4 |        2 |        4 |
| Susan   |     5 |        1 |        4 |        2 |        1 |        1 |        1 |
| Zara    |     5 |        4 |        3 |        4 |        3 |        4 |        3 |
+---------+-------+----------+----------+----------+----------+----------+----------+

```

The rank of the student must be stored for the days like shown here, for the day 1, the ranks must be stored in a column/anything similar, and the number of days must go on for the consecutive 180 days, the ranks for each day must be added to the consecutive days.

I'm not stuck with the save method, but about the field where to save the calculated ranks.