Add deploy strategy related predefined variables

app/models/project_auto_devops.rb

@@ -25,6 +25,11 @@ class ProjectAutoDevops < ActiveRecord::Base
         variables.append(key: 'AUTO_DEVOPS_DOMAIN',
                          value: domain.presence || instance_domain)
       end
+
+      if continuous?
+        variables.append(key: 'STAGING_ENABLED', value: 1)
+        variables.append(key: 'INCREMENTAL_ROLLOUT_ENABLED', value: 1)
+      end
     end
   end
 end

spec/factories/project_auto_devops.rb

@@ -3,5 +3,6 @@ FactoryBot.define do
     project
     enabled true
     domain "example.com"
+    deploy_strategy :continuous
   end
 end

spec/models/project_auto_devops_spec.rb

@@ -69,6 +69,19 @@ describe ProjectAutoDevops do
       end
     end
 
+    context 'when deploy_strategy is continuous' do
+      let(:domain) { 'example.com' }
+
+      before do
+        auto_devops.deploy_strategy = 'continuous'
+      end
+
+      it do
+        expect(auto_devops.predefined_variables.map { |var| var[:key] })
+          .to include("STAGING_ENABLED", "INCREMENTAL_ROLLOUT_ENABLED")
+      end
+    end
+
     def domain_variable
       { key: 'AUTO_DEVOPS_DOMAIN', value: 'example.com', public: true }
     end