FEATURE: new 'poll:migrate_old_polls' rake task

plugins/poll/lib/tasks/migrate_old_polls.rake

@@ -0,0 +1,41 @@
+desc "Migrate old polls to new syntax"
+task "poll:migrate_old_polls" => :environment do
+  # iterate over all polls
+  PluginStoreRow.where(plugin_name: "poll")
+                .where("key LIKE 'poll_options_%'")
+                .pluck(:key)
+                .each do |poll_options_key|
+    # extract the post_id
+    post_id = poll_options_key["poll_options_".length..-1].to_i
+    # load the post from the db
+    if post = Post.find_by(id: post_id)
+      putc "."
+      # go back in time
+      Timecop.freeze(post.created_at + 1.minute) do
+        # fix the RAW when needed
+        if post.raw !~ /\[poll\]/
+          first_list = /(^- .+?$\n)\n/m.match(post.raw)[0]
+          post.raw = post.raw.sub(first_list, "[poll]\n#{first_list}\n[/poll]")
+        else
+          post.raw = post.raw + " "
+        end
+        # save the poll
+        post.save
+        # iterate over all votes
+        PluginStoreRow.where(plugin_name: "poll")
+                      .where("key LIKE 'poll_vote_#{post_id}_%'")
+                      .pluck(:key, :value)
+                      .each do |poll_vote_key, vote|
+          # extract the user_id
+          user_id = poll_vote_key["poll_vote_#{post_id}_%".length..-1].to_i
+          # conver to MD5 (use the same algorithm as the client-side poll dialect)
+          options = [Digest::MD5.hexdigest([vote].to_json)]
+          # submit vote
+          DiscoursePoll::Poll.vote(post_id, "poll", options, user_id) rescue nil
+        end
+      end
+    end
+  end
+
+  puts "", "Done!"
+end