Add on_winner_choose hook

Author: macgena

README.md

@@ -386,6 +386,8 @@ Split.configure do |config|
   # before experiment reset or deleted
   config.on_before_experiment_reset  = -> (example) { # Do something on reset }
   config.on_before_experiment_delete = -> (experiment) { # Do something else on delete }
+  # after experiment winner had been set
+  config.on_winner_choose = -> (experiment) { # Do something on winner choose }
 end
 ```
 

lib/split/configuration.rb

@@ -20,6 +20,7 @@ class Configuration
     attr_accessor :on_experiment_reset
     attr_accessor :on_experiment_delete
     attr_accessor :on_before_experiment_reset
+    attr_accessor :on_winner_choose
     attr_accessor :on_before_experiment_delete
     attr_accessor :include_rails_helper
     attr_accessor :beta_probability_simulations
@@ -216,6 +217,7 @@ def initialize
       @on_experiment_delete = proc{|experiment|}
       @on_before_experiment_reset = proc{|experiment|}
       @on_before_experiment_delete = proc{|experiment|}
+      @on_winner_choose = proc{|experiment|}
       @db_failover_allow_parameter_override = false
       @allow_multiple_experiments = false
       @enabled = true

lib/split/experiment.rb

@@ -155,6 +155,7 @@ def has_winner?
     def winner=(winner_name)
       redis.hset(:experiment_winner, name, winner_name.to_s)
       @has_winner = true
+      Split.configuration.on_winner_choose.call(self)
     end
 
     def participant_count

spec/experiment_spec.rb

@@ -118,7 +118,7 @@ def alternative(color)
       experiment = Split::Experiment.new('basket_text', :alternatives => ['Basket', "Cart"], :resettable => false)
       expect(experiment.resettable).to be_falsey
     end
-    
+
     context 'from configuration' do
       let(:experiment_name) { :my_experiment }
       let(:experiments) do
@@ -130,7 +130,7 @@ def alternative(color)
       end
 
       before { Split.configuration.experiments = experiments }
-      
+
       it 'assigns default values to the experiment' do
         expect(Split::Experiment.new(experiment_name).resettable).to eq(true)
       end
@@ -233,12 +233,17 @@ def alternative(color)
   end
 
   describe 'winner=' do
-    it "should allow you to specify a winner" do
+    it 'should allow you to specify a winner' do
       experiment.save
       experiment.winner = 'red'
       expect(experiment.winner.name).to eq('red')
     end
 
+    it 'should call the on_winner_choose hook' do
+      expect(Split.configuration.on_winner_choose).to receive(:call)
+      experiment.winner = 'green'
+    end
+
     context 'when has_winner state is memoized' do
       before { expect(experiment).to_not have_winner }