Put back filter_to_json:to_json/2, which had been mistakenly removed in a previous commit
Put back filter_to_json:to_json/2, which had been mistakenly removed in a previous commit

erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta