add message model and migration

app/admin/messages.rb

@@ -0,0 +1,22 @@
+ActiveAdmin.register Message do
+  csv do
+    column :title
+    column(:email)
+    column('bODY', humanize_name: false) # preserve case
+  end
+  # See permitted parameters documentation:
+  # https://github.com/activeadmin/activeadmin/blob/master/docs/2-resource-customization.md#setting-up-strong-parameters
+  #
+  # Uncomment all parameters which should be permitted for assignment
+  #
+  permit_params :title, :description, :email, :phone
+  #
+  # or
+  #
+  # permit_params do
+  #   permitted = [:title, :description, :email, :phone]
+  #   permitted << :other if params[:action] == 'create' && current_user.admin?
+  #   permitted
+  # end
+  
+end

app/models/message.rb

@@ -0,0 +1,2 @@
+class Message < ApplicationRecord
+end