diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fcf3b18..06e6aa9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,49 +6,51 @@ on:
     branches: [ main ]
 
 jobs:
-  scan_ruby:
+  build_test: # all steps run in dev container
     runs-on: ubuntu-latest
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Run brakeman
-        uses: devcontainers/ci@v0.3
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v2 
         with:
-          runCmd: bin/brakeman --no-pager
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
 
-  lint:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+      - name: Build Dev Container task
+        uses: devcontainers/ci@v0.3
         with:
-          ruby-version: .ruby-version
-          bundler-cache: true
+          imageName: ghcr.io/astral-devcontainer
+          cacheFrom: ghcr.io/astral-devcontainer
+          push: never
+          runCmd: |
+            # Add multiple commands to run if needed
+            bundle install
 
       - name: Lint code for consistent style
-        run: bin/rubocop -f github
-
-  test:
-    runs-on: ubuntu-latest
-
-    # services:
-    #  redis:
-    #    image: redis
-    #    ports:
-    #      - 6379:6379
-    #    options: --health-cmd "redis-cli ping" --health-interval 10s --health-timeout 5s --health-retries 5
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
+        uses: devcontainers/ci@v0.3
+        with:
+          imageName: ghcr.io/astral-devcontainer
+          cacheFrom: ghcr.io/astral-devcontainer
+          push: never
+          runCmd: bin/rubocop -f github
+  
+      - name: Run brakeman
+        uses: devcontainers/ci@v0.3
+        with:
+          imageName: ghcr.io/astral-devcontainer
+          cacheFrom: ghcr.io/astral-devcontainer
+          push: never
+          runCmd: bin/brakeman --no-pager
 
       - name: Run tests
         uses: devcontainers/ci@v0.3
         with:
+          imageName: ghcr.io/astral-devcontainer
+          cacheFrom: ghcr.io/astral-devcontainer
+          push: never
           runCmd: bin/rails test
 
       - name: Keep screenshots from failed system tests
diff --git a/README.md b/README.md
index 335d513..03ab0fa 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # README
 
-Astral-rails is a proof-of-concept api application intended to simplify
+Astral is an api-only application intended to simplify
 certificate acquisition for other applications/services. Broadly speaking,
 it will: 
 
@@ -10,18 +10,21 @@ it will:
 
 # Running
 
-This app is most easily run and developed in its devcontainer.
+This Rails app is most easily run and developed in its devcontainer.
 
 1) Open in devcontainer
 2) Launch server using vscode launch config, or in terminal run:
 ```
 rails s
 ```
-3) POST /certificates to acquire cert in terminal:
+3) POST /certificates to acquire cert in another terminal (need to provide `common_name` param):
 ```
 curl -X POST http://localhost:3000/certificates \
 -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJqb2huLmRvZUBleGFtcGxlLmNvbSIsIm5hbWUiOiJKb2huIERvZSIsImlhdCI6MTUxNjIzOTAyMiwiZ3JvdXBzIjpbImdyb3VwMSIsImdyb3VwMiJdLCJhdWQiOiJhc3RyYWwifQ.tfRLXmE_eq-piP88_clwPWrYfMAQbCJAeZQI6OFxZSI" \
 -H "Content-type: application/json" \
 -d "{ \"common_name\": \"example.com\" }"
 ```
-
+4) Run the tests from devcontainer terminal:
+```
+rails test
+```
diff --git a/test/interactors/obtain_cert_test.rb b/test/interactors/obtain_cert_test.rb
index e423811..3211ae2 100644
--- a/test/interactors/obtain_cert_test.rb
+++ b/test/interactors/obtain_cert_test.rb
@@ -24,7 +24,7 @@ def setup
     Services::CertificateService.stub :new, srv do
       context = @interactor.call(request: request)
       assert context.failure?
-      assert_equal nil, context.cert
+      assert_nil context.cert
     end
   end
 end