mod reports: include reported user and message in forum post.

Also fix it so that reports against dmails include the key in the dmail
link so that mods can view the reported dmail.

test/unit/moderation_reports_test.rb

@@ -0,0 +1,15 @@
+require 'test_helper'
+
+class ModerationReportTest < ActiveSupport::TestCase
+  context "Moderation reports: " do
+    context "creating a moderation report" do
+      should "create a forum post" do
+        @dmail = create(:dmail)
+        @modreport = create(:moderation_report, model: @dmail, reason: "blah")
+
+        assert_equal(2, ForumPost.count)
+        assert_match(/blah/, ForumPost.last.body)
+      end
+    end
+  end
+end