diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 101f5328bd1683fab862067f8ffa438ee17fd3df..0b192d108f201552238b449dba5eea5733f66bc4 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -33,7 +33,7 @@ build_db:
     refs:
       - master
     changes:
-      - database
+      - database/*
   script:
     - cd database
     - docker login -u "${CI_REGISTRY_USER}" -p "${CI_REGISTRY_PASSWORD}" "${CI_REGISTRY}"
diff --git a/README.md b/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..77c3eadbcecceef67e16c93c52f36e165c76f7d0
--- /dev/null
+++ b/README.md
@@ -0,0 +1,28 @@
+## Setup
+
+    docker-compose pull
+    docker-compose up -d
+
+If you experience issues with the pull command use this setting in `/etc/docker/daemon.json`:
+
+    {
+        "insecure-registries" : [ "git.ia2.inaf.it:5050" ]
+    }
+
+## Demo
+
+    ./call-tap.sh badtoken
+
+Only free records (2 rows)
+
+    ./call-tap.sh token1
+
+Free records + records associated with group1 and group2 (6 rows)
+
+    ./call-tap.sh token2
+
+Free records + records associated with group2 (4 rows)
+
+## Shutdown
+
+    docker-compose down
diff --git a/call-tap.sh b/call-tap.sh
new file mode 100755
index 0000000000000000000000000000000000000000..f2583a02991e619914ff8e2aa31d286577556d0b
--- /dev/null
+++ b/call-tap.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+
+if [ "$#" -ne 1 ]; then
+    echo "Usage: $0 <token>"
+    exit 1
+fi
+
+curl -s -XPOST \
+        -H "Authorization: Bearer $1" \
+        -F 'REQUEST=doQuery' \
+        -F 'LANG=ADQL' \
+        -F 'FORMAT=text/csv' \
+        -F 'PHASE=RUN' \
+        -F "QUERY=SELECT * from demo.private_rows;" \
+        http://localhost:8080/tap/sync
diff --git a/database/04-vollt-fix.sql b/database/04-vollt-fix.sql
new file mode 100644
index 0000000000000000000000000000000000000000..3f01fc60258ec287707ae80e02b0061b80228297
--- /dev/null
+++ b/database/04-vollt-fix.sql
@@ -0,0 +1,2 @@
+update "TAP_SCHEMA".columns set arraysize = replace(arraysize, '*', '') where arraysize like '%*%';
+update "TAP_SCHEMA".columns set arraysize = NULL where arraysize = '';