lotus/controller — pull request #41 by rail44 (2014-09-11 10:17:13+00:00)
Title: Add block validation for Action::Param

Hi.

Thin bring block validation for Action::Param.
See https://github.com/lotus/validations/pull/13 .

e.g.
```
params do
param :email, presence: true, format: /\A.+@.+\z/
param :name, presence: true
param :tos, acceptance: true
param :block do |value|
if value == 'foo'
[true, 'bar']
else
[false, 'Foo']
end
end
end
```