Validate year of release about mystamps

[php-coder]

Because we already have a check for the year in future (see #8) then here we just need to check that the year >= 1840. I suggest to use @Min annotation for that.

[cssru]

Ага, а я думал - на стороне клиента проверку реализовать.

[php-coder]

Technically it's already "validated" on the client side -- there is a select with options from 1840 to 2016. So, user couldn't choose the year less than 1840. But... this check intended not for ordinary users :)

[cssru]

Year, angry users may want to put your app down, right?

[php-coder]

:-) No, probably, it can't break the application, but a) I want to be sure that my data satisfies the constraints b) it's a trivial task that could be accomplished by newcomers :)

BTW, if we would use PostgreSQL, for instance, we could add a CHECK() constraint (I don't try it, but looks like we could).

Another idea about protecting the data is: maybe we would write some logic that operates on the series' year and if someone put -1 as the year this logic goes crazy :)