Capistrano - deployment email with list of git commits

gistfile1.txt

namespace :release do 
  desc "get current commit in remote server"
  task :before do
    begin 
    remote_sha = capture("cd #{current_path}; git rev-parse --verify HEAD")    
    set :remote_before_commit, remote_sha.strip
    # first time deploy can throw exception
    rescue 
    end
  end
    task :set_release_notes do      
      after_deploy_sha = capture("cd #{current_path}; git rev-parse --verify HEAD")

      if defined?(remote_before_commit) and !remote_before_commit.blank?
        git_commits_range = "#{remote_before_commit.strip}..#{after_deploy_sha.strip}"
      #supports first release(prints many commits till last one)
      else
        git_commits_range = after_deploy_sha.strip
      end
      git_log = `git log #{git_commits_range}` # executes in local shell
      set :release_notes, git_log
      set :deployed_commit, after_deploy_sha.strip
  end
end

before "deploy", "release:before"

# Notify via mail on the deployed commits
after "deploy:update", "release:set_release_notes", "deploy:notify"