adds filtering of spending proposals by admin

app/models/spending_proposal.rb

@@ -23,10 +23,36 @@ class SpendingProposal < ActiveRecord::Base
   scope :valuating, -> { where("valuation_assignments_count > 0 AND valuation_finished = ?", false) }
   scope :valuation_finished, -> { where(valuation_finished: true) }
 
+  scope :for_render, -> { includes(:geozone, administrator: :user, valuators: :user) }
+
   def description
     super.try :html_safe
   end
 
+  def self.search(params, current_filter)
+    results = self
+    results = results.by_geozone(params[:geozone_id])             if params[:geozone_id].present?
+    results = results.by_administrator(params[:administrator_id]) if params[:administrator_id].present?
+    results = results.send(current_filter)                        if current_filter.present?
+    results = results.for_render
+    results
+  end
+
+  def self.by_geozone(geozone)
+    case geozone
+    when nil
+      self
+    when 'all'
+      where(geozone_id: nil)
+    else
+      where(geozone_id: geozone.presence)
+    end
+  end
+
+  def self.by_administrator(administrator)
+    where(administrator_id: administrator.presence)
+  end
+
   def feasibility
     case feasible
     when true