Validate multiple contexts on `valid?` and `invalid?` at once.

Example:

```ruby
class Person
  include ActiveModel::Validations

  attr_reader :name, :title
  validates_presence_of :name, on: :create
  validates_presence_of :title, on: :update
end

person = Person.new
person.valid?([:create, :update])    # => true
person.errors.messages               # => {:name=>["can't be blank"], :title=>["can't be blank"]}
```

1 files changed, 1 insertions, 1 deletions

diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 5f1dde4aa3..f23c920d87 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -162,7 +162,7 @@ module ActiveModel
           options = options.dup
           options[:if] = Array(options[:if])
           options[:if].unshift ->(o) {
-            Array(options[:on]).include?(o.validation_context)
+            !(Array(options[:on]) & Array(o.validation_context)).empty?
           }
         end