Added total_scores method

README.markdown

@@ -350,6 +350,7 @@ Competition ranking: The `CompetitionRankingLeaderboard` subclass of `Leaderboar
   total_members: Total # of members in the leaderboard
   total_pages: Total # of pages in the leaderboard given the leaderboard's page_size
   total_members_in_score_range(min_score, max_score): Count the number of members within a score range in the leaderboard
+  total_scores: Sum of scores for all members in leaderboard
   change_score_for(member, delta): Change the score for a member by some amount delta (delta could be positive or negative)
   rank_for(member): Retrieve the rank for a given member in the leaderboard
   score_for(member): Retrieve the score for a given member in the leaderboard

lib/leaderboard.rb

@@ -369,6 +369,13 @@ def total_members_in_score_range_in(leaderboard_name, min_score, max_score)
     @redis_connection.zcount(leaderboard_name, min_score, max_score)
   end
 
+  # Sum of scores for all members in leaderboard
+  #
+  # @return Sum of scores for all members in leaderboard
+  def total_scores
+    all_leaders.map{|hash| hash[:score] }.inject(0, :+)
+  end
+
   # Change the score for a member in the leaderboard by a score delta which can be positive or negative.
   #
   # @param member [String] Member name.

spec/leaderboard_spec.rb

@@ -855,4 +855,10 @@
     leaders = @leaderboard.ranked_in_list(['member_200'], :include_missing => false, :with_member_data => true)
     expect(leaders.size).to be(0)
   end
+
+  it 'should return the sum of all scores in the leaderboard' do
+    rank_members_in_leaderboard(25)
+
+    expect(@leaderboard.total_scores()).to eq(325)
+  end
 end