Bring back testing with MySQL

The original reason was after the `rank` becoming a protected keyword. As we depend on doctrine as abrstraction a lot it is good to verify that the translation is reasonable on backend SQL servers of whatever dialect.

.github/workflows/integration.yml

@@ -14,19 +14,24 @@ jobs:
     strategy:
       matrix:
         SQL_ISOLATION: ['REPEATABLE-READ', 'SERIALIZABLE']
+        include:
+          - sql: mariadb
+            sql_options: --health-cmd="healthcheck.sh --connect --innodb_initialized" --health-interval=10s --health-timeout=5s --health-retries=3
+          - sql: mysql
+            sql_options: --health-cmd="mysqladmin ping" --health-interval=5s --health-timeout=2s --health-retries=3
     container:
       image: domjudge/gitlabci:24.04
       options: --privileged --cgroupns=host --init
     services:
       sqlserver:
-        image: mariadb
+        image: ${{ matrix.sql }}
+        options: ${{ matrix.sql_options }}
         ports:
           - 3306:3306
         env:
           MYSQL_ROOT_PASSWORD: root
           MYSQL_USER: domjudge
           MYSQL_PASSWORD: domjudge
-        options: --health-cmd="healthcheck.sh --connect --innodb_initialized" --health-interval=10s --health-timeout=5s --health-retries=3
     steps:
       - uses: actions/checkout@v4
       - name: info
@@ -86,13 +91,13 @@ jobs:
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@v4
         with:
-          name: DB-dump-${{ matrix.SQL_ISOLATION }}
+          name: DB-dump-${{ matrix.SQL_ISOLATION }}-${{ matrix.sql }}
           path: /tmp/db.sql
       - name: Upload all logs/artifacts
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@v4
         with:
-          name: Logs-${{ matrix.SQL_ISOLATION }}
+          name: Logs-${{ matrix.SQL_ISOLATION }}-${{ matrix.sql }}
           path: |
             /var/log/nginx
             /opt/domjudge/domserver/webapp/var/log/*.log