Simple release-notes from your git log ('per-week' approach)

git_log.rb

# usage: (after download this file to your repo folder)
# $ cd git_repo
# $ ruby git_log.rb >> release_notes.txt

require 'time'

class Commit
  def rows
    @rows ||= []
  end
  def date
    @date ||= (Time.parse(@rows.detect{ |r| r.start_with? 'Date: ' }[5..-1].strip).to_date)
  end
  def content
    @content ||= @rows.reject do |row|
      row.strip == '' or row.start_with? 'Author: ' or row.start_with? 'Date: ' or row.start_with? 'commit '
    end
  end
  def valid?
    @rows.size > 3
  end
end

class Reader
  def initialize
    @commits = []
  end
  def start
    %x[git log].split("\n").inject([]) do |commits, line|
      if line.start_with? 'commit'
        @commits << Commit.new
      end
      @commits.last.rows << line
    end
  end
  def sort
    @commits.sort! do |one, another|
      one.date <=> another.date
    end
  end
  def result
    @commits
  end
end

class Printer
  def initialize(commits)
    @commits = commits
    @last_date = nil
    @last_week = nil
  end
  def go
    @commits.each do |commit|
      if @last_week != commit.date.cweek
        @last_date = commit.date
        @last_week = commit.date.cweek
        puts "Semana: #{@last_week}. Data: #{@last_date.strftime '%d/%m/%Y'}"
      end
      commit.content.each do |c|
        puts " - - - #{c}"
      end
    end
  end
end

Printer.new(Reader.new.tap(&:start).tap(&:sort).result).go