Add spec for pwa installation instructions

Author: rossta

spec/requests/pwa/installation_instructions_spec.rb

@@ -0,0 +1,11 @@
+require "rails_helper"
+
+RSpec.describe "/pwa/installation_instructions", type: :request do
+  describe "GET /pwa/installation_instructions" do
+    it "succeeds" do
+      get "/pwa/installation_instructions"
+
+      expect(response).to have_http_status(:success)
+    end
+  end
+end