Add Rails master key to CI tests

The value is needed to initialise Rails during testing

.github/workflows/build_and_deploy.yml

@@ -96,6 +96,7 @@ jobs:
         with:
           build-args: |
             BUILDKIT_INLINE_CACHE=1
+            RAILS_MASTER_KEY=${{ secrets.RAILS_MASTER_KEY }}
           # Cache from builder target tagged with branch name, may be empty first time branch is pushed
           # Cache from builder target tagged with main branch name, always present, maybe less recent
           cache-from: |
@@ -112,6 +113,7 @@ jobs:
           build-args: |
             BUILDKIT_INLINE_CACHE=1
             COMMIT_SHA=${{ env.COMMIT_SHA }}
+            RAILS_MASTER_KEY=${{ secrets.RAILS_MASTER_KEY }}
           # Cache from builder target built above, always present
           # Cache from production target tagged with branch name, may be empty first time branch is pushed
           # Cache from production target tagged with main branch name, always present, maybe less recent

.github/workflows/lint.yml

@@ -72,8 +72,9 @@ jobs:
     runs-on: ubuntu-20.04
 
     env:
-      RAILS_ENV: test
       DATABASE_URL: postgis://postgres:postgres@localhost:5432/tvs_test
+      RAILS_ENV: test
+      RAILS_MASTER_KEY: ${{ secrets.RAILS_MASTER_KEY }}
 
     services:
       postgres:

.github/workflows/test.yml

@@ -32,8 +32,9 @@ jobs:
             params: '--exclude-pattern "spec/{system}/*_spec.rb, spec/system/{jobseekers,publishers,support_users,other}/*_spec.rb"'
 
     env:
-      RAILS_ENV: test
       DATABASE_URL: postgis://postgres:postgres@localhost:5432/tvs_test
+      RAILS_ENV: test
+      RAILS_MASTER_KEY: ${{ secrets.RAILS_MASTER_KEY }}
 
     services:
       postgres:

Dockerfile

@@ -32,9 +32,11 @@ COPY . .
 # configuring it using the ENV variables we provide in storage.yml. However, at this point, these ENV vars have not been loaded,
 # causing the error. Below we define two throaway ENV vars to prevent the error from being thrown. These are then later overwritten,
 # when all of the ENV vars are loaded.
+ARG RAILS_MASTER_KEY
 
 ENV DOCUMENTS_S3_BUCKET=throwaway_value
 ENV SCHOOLS_IMAGES_LOGOS_S3_BUCKET=throwaway_value
+ENV RAILS_MASTER_KEY=$RAILS_MASTER_KEY
 
 RUN RAILS_ENV=production SECRET_KEY_BASE=required-to-run-but-not-used RAILS_SERVE_STATIC_FILES=1 bundle exec rake assets:precompile