Added newsletter model and UserSegments class

lib/user_segments.rb

@@ -0,0 +1,42 @@
+class UserSegments
+  def self.all_users
+    User.newsletter.active
+  end
+
+  def self.proposal_authors
+    author_ids = Proposal.not_archived.not_retired.pluck(:author_id).uniq
+    author_ids(author_ids)
+  end
+
+  def self.investment_authors
+    author_ids = current_budget_investments.pluck(:author_id).uniq
+    author_ids(author_ids)
+  end
+
+  def self.feasible_and_undecided_investment_authors
+    author_ids = current_budget_investments.where(feasibility: %w(feasible undecided))
+                                           .pluck(:author_id).uniq
+
+    author_ids(author_ids)
+  end
+
+  def self.selected_investment_authors
+    author_ids = current_budget_investments.selected.pluck(:author_id).uniq
+    author_ids(author_ids)
+  end
+
+  def self.winner_investment_authors
+    author_ids = current_budget_investments.winners.pluck(:author_id).uniq
+    author_ids(author_ids)
+  end
+
+  private
+
+  def self.current_budget_investments
+    Budget.current.investments
+  end
+
+  def self.author_ids(author_ids)
+    all_users.where(id: author_ids)
+  end
+end