Fix DBValidationNumberRangeRule

I was replace this line 
`NSNumber *numberValue = [self.object valueForKey:self.keyPath];`
with
`NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
    f.numberStyle = NSNumberFormatterDecimalStyle;
    NSNumber *numberValue = [f numberFromString:[self.object valueForKey:self.keyPath]];
    if (numberValue == nil) return NO;`
You can check.
Best regards
