Dataset unique elements

Closes #1713 (closed)

arkindex/training/models.py

@@ -266,6 +266,7 @@ class Dataset(models.Model):
     name = models.CharField(max_length=100, validators=[MinLengthValidator(1)])
     description = models.TextField(validators=[MinLengthValidator(1)])
     state = EnumField(DatasetState, default=DatasetState.Open, max_length=50)
+    unique_elements = models.BooleanField(default=True)
 
     class Meta:
         constraints = [