FIX: `moderators` group wasn't being updated to be messagable by everyone.

https://meta.discourse.org/t/custom-flag-not-showing-text/76244

app/models/group.rb

@@ -268,10 +268,13 @@ class Group < ActiveRecord::Base
 
     # the everyone group is special, it can include non-users so there is no
     # way to have the membership in a table
-    if name == :everyone
+    case name
+    when :everyone
       group.visibility_level = Group.visibility_levels[:owners]
       group.save!
       return group
+    when :moderators
+      group.update!(messageable_level: ALIAS_LEVELS[:everyone])
     end
 
     # Remove people from groups they don't belong in.

spec/models/group_spec.rb

@@ -206,6 +206,14 @@ describe Group do
       expect(g.visibility_level).to eq(Group.visibility_levels[:owners])
     end
 
+    it "ensures that the moderators group is messageable by all" do
+      group = Group.find(Group::AUTO_GROUPS[:moderators])
+      group.update!(messageable_level: Group::ALIAS_LEVELS[:nobody])
+      Group.refresh_automatic_group!(:moderators)
+
+      expect(group.reload.messageable_level).to eq(Group::ALIAS_LEVELS[:everyone])
+    end
+
     it "does not reset the localized name" do
       begin
         default_locale = SiteSetting.default_locale