[BREAK UPSTREAM] add sage theme circleci config

Author: matbrady

.circleci/config.yml

@@ -107,6 +107,10 @@ jobs:
           name: run PHP build step
           command: ./.ci/build/php
 
+      - run:
+          name: install theme composer dependencies
+          command: cd web/wp-content/themes/sage && composer install
+
       - save_cache:
           key: vendor-{{ checksum "composer.lock" }}
           paths:
@@ -118,6 +122,41 @@ jobs:
             - web
             - vendor
 
+  build_yarn:
+    <<: *defaults
+    docker:
+      - image: circleci/node:10.16.2
+
+    steps:
+      - checkout
+
+      - restore_cache:
+          keys:
+            - yarn-packages-{{ checksum "web/wp-content/themes/sage/yarn.lock" }}
+            - yarn-packages- # used if checksum fails
+
+      - run:
+          name: install theme yarn dependencies
+          command: cd web/wp-content/themes/sage && yarn install
+
+      - run:
+          name: build theme assets
+          # If non-hashed versions of site assets are needed for 3rd parties, also run `yarn build:nohash`
+          command: cd web/wp-content/themes/sage && yarn build
+
+      - save_cache:
+          name: cache Yarn files
+          key: yarn-packages-{{ checksum "web/wp-content/themes/sage/yarn.lock" }}
+          paths:
+            - $HOME/.cache/yarn
+
+      - persist_to_workspace:
+          # Must be relative path from working_directory
+          root: .
+          # Must be relative path from root
+          paths:
+            - web/wp-content/themes/sage/dist
+
   deploy_to_pantheon:
     <<: *defaults
     steps:
@@ -231,10 +270,12 @@ workflows:
     jobs:
       - configure_env_vars
       # - static_tests
+      - build_yarn
       - build_php
       - deploy_to_pantheon:
           requires:
             # - static_tests
+            - build_yarn
             - build_php
       # - visual_regression_test:
       #     requires: