Add communities and topics

app/controllers/communities_controller.rb

@@ -0,0 +1,19 @@
+class CommunitiesController < ApplicationController
+
+  before_action :set_community, :load_topics, only: :show
+
+  skip_authorization_check
+
+  def show
+  end
+
+  private
+
+  def set_community
+    @community = Community.find(params[:id])
+  end
+
+  def load_topics
+    @topics = @community.topics
+  end
+end