Add out-of-date notice to admin overview (#20172)

app/views/admin/overview/_notices.html.erb

@@ -0,0 +1,11 @@
+
+<% if ForemInstance.deployed_at.to_i.positive? && ForemInstance.deployed_at < 2.weeks.ago %>
+  <div class="crayons-notice crayons-notice--<%= ForemInstance.deployed_at < 4.weeks.ago ? "danger" : "warning" %> mb-6">
+    <p class="p-1">
+      It has been <strong><%= time_ago_in_words ForemInstance.deployed_at %></strong> since this Forem was deployed. We recommend you <a href="https://github.com/forem/forem" class="fw-bold">re-deploy from the main branch</a> to stay up-to-date.
+    </p>
+    <p class="p-1 py-2 fs-s">
+      If you stay out of date for too long, it greatly increases the risk that something could go wrong when you try to re-deploy.
+    </p>
+  </div>
+<% end %>

app/views/admin/overview/index.html.erb

@@ -3,6 +3,7 @@
 <h1 class="crayons-title mb-4">
   Overview
 </h1>
+<%= render "notices" %>
 
 <div class="flex flex-col gap-4">
   <div class="flex flex-col l:flex-row gap-4">

spec/requests/admin/overview_spec.rb

@@ -8,6 +8,31 @@ RSpec.describe "/admin" do
     allow(FeatureFlag).to receive(:enabled?).and_call_original
   end
 
+  describe "Notices" do
+    it "does not show warning if deployed at is recent" do
+      allow(ForemInstance).to receive(:deployed_at).and_return(1.day.ago)
+      get admin_path
+
+      expect(response.body).not_to include("If you stay out of date for too long")
+    end
+
+    it "shows warning notice if deployed at is over two weeks ago" do
+      allow(ForemInstance).to receive(:deployed_at).and_return(3.weeks.ago)
+      get admin_path
+
+      expect(response.body).to include("If you stay out of date for too long")
+      expect(response.body).to include("crayons-notice--warning")
+    end
+
+    it "shows danger notice if deployed at is over four weeks ago" do
+      allow(ForemInstance).to receive(:deployed_at).and_return(5.weeks.ago)
+      get admin_path
+
+      expect(response.body).to include("If you stay out of date for too long")
+      expect(response.body).to include("crayons-notice--danger")
+    end
+  end
+
   describe "Last deployed and Latest Commit ID card" do
     before do
       ForemInstance.instance_variable_set(:@deployed_at, nil)