ruby/ruby — pull request #690 by joker1007 (2014-07-30 08:19:18+00:00)
Title: Add description of `BigDecimal.new` exceptions

`BigDecimal.new` raises some Exceptions.
But it is undocumented.

this PR is very similar to #680.
But #680 seems still not enough.

Especially, ArgumentError by larger digits value than Float::DIG + 1 causes some trouble.