Create a model named `EventHistory`
user
```ruby
class EventHistory < ApplicationRecord
  belongs_to :dojo

  validates :dojo_name, presence: true
  validates :service_name, presence: true, uniqueness: { scope: :event_id  }
  validates :service_group_id, presence: true
  validates :event_id, presence: true
  validates :event_url, presence: true, uniqueness: true, allow_nil: true
  validates :participants, presence: true
  validates :evented_at, presence: true
end
```
assistant