LGA-1773 Cla Common update (#121)

 LGA-1773 - Moved cla_common.money_interval.serializers module to cla_backend as that was the only application that used it and requires changes to make it work with DRF 3.0

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Co-authored-by: said-moj <45761276+said-moj@users.noreply.github.com>

cla_common/money_interval/fields.py

@@ -92,15 +92,18 @@ class MoneyIntervalField(models.BigIntegerField):
 
     def __init__(self, max_value=9999999999, min_value=0, *args, **kwargs):
         self.max_value, self.min_value = max_value, min_value
-        # kwargs['coerce'] = kwargs.pop('coerce', int)
-        # kwargs['widget'] = forms.NumberInput
-
-        super(MoneyIntervalField, self).__init__(*args, **kwargs)
+        kwargs.setdefault("validators", [])
 
         if max_value is not None:
-            self.validators.append(validators.MaxValueValidator(max_value))
+            max_validator = validators.MaxValueValidator(max_value)
+            if max_validator not in kwargs["validators"]:
+                kwargs["validators"].append(max_validator)
         if min_value is not None:
-            self.validators.append(validators.MinValueValidator(min_value))
+            min_validator = validators.MinValueValidator(min_value)
+            if min_validator not in kwargs["validators"]:
+                kwargs["validators"].append(min_validator)
+
+        super(MoneyIntervalField, self).__init__(*args, **kwargs)
 
     def contribute_to_class(self, cls, name):
         # first, create the hidden fields. It is *crucial* that these