New gathering associations.rb

class User < AR::Base
  has_many :gathering_participations
  has_many :gatherings, :through => :gathering_participations
  has_many :gathering_suggestions
  has_many :gathering_votes
end

class GatheringParticipation
  belongs_to :user
  belongs_to :gathering
  has_many :gathering_votes
  has_many :gathering_suggestions
end

class GatheringSuggestion
  belongs_to :user
  belongs_to :gathering
  belongs_to :gathering_participation
  has_many :gathering_votes
end

class GatheringVote
  belongs_to :gathering_suggestion
  belongs_to :gathering_participation
  belongs_to :gathering
  belongs_to :user
end

class Gathering
  has_many :gathering_participations
  has_many :users, :through => :gathering_participations
  has_many :gathering_suggestions
  has_many :gathering_votes
  has_many :voted_suggestions, :through => :gathering_votes # etc
end