diff --git a/README.md b/README.md
index d390895bb..c4037b4a9 100644
--- a/README.md
+++ b/README.md
@@ -84,7 +84,7 @@ yarn dev:rollup
 
 #### Database migrations
 
-Database migrations are run automatically when the _production_ app starts. In _development_, you'll have to run them manually:
+Database migrations are run automatically when a production build of the app starts. In _development_, you'll have to run them manually:
 
 ```sh
 yarn db:migrate:dev
@@ -94,6 +94,18 @@ Migrations are located in `db-migrations/`. Write SQL or JS migrations and follo
 
 For detailed instructions, please refer to the [postgres-migrations](https://github.com/thomwright/postgres-migrations) documentation.
 
+⚠️ On Vercel environments like "preview" and "production", "production" build are started which means that database migrations are executed.
+Since all environments are sharing the same database, it means that a database migration executing on 1 database could be disruptive to
+other preview deployments. For example adding a column to the schema would be disruptive, since other preview deployments would try to
+remove it (since the column is not yet in the schema). To prevent any problems on preview deployments, we have a second database that
+is special for development and that must be used if you are working on a branch that brings in database changes. You can configure
+this in the Vercel environment variables by copy-pasting the environment variables found in the [visualization-tool-postgres-dev][]
+storage (see `.env.local` tab), and copy paste them as [environment variables](https://vercel.com/ixt/visualization-tool/settings/environment-variables)
+in the visualisation-project. Take care of scoping the new environment variables to the preview branch you are working on.
+After merging the branch, you can delete the environment variables scoped to the branch.
+
+[visualization-tool-postgres-dev](https://vercel.com/ixt/visualization-tool/stores/postgres/store_dV3rog1asOXO3BfC/data)
+
 ## Versioning
 
 New versions of `package.json` are built on GitLab CI into a separate image that will be deployed to the integration env.
diff --git a/app/prisma/schema.prisma b/app/prisma/schema.prisma
index 77f2e7a7c..8244fa5ed 100644
--- a/app/prisma/schema.prisma
+++ b/app/prisma/schema.prisma
@@ -32,6 +32,10 @@ model User {
   id     Int      @id @default(autoincrement())
   sub    String?  @unique @db.VarChar(64)
   name   String?  @db.VarChar(100)
+  last_login DateTime? @db.Timestamp(6)
+  created_at DateTime @default(now()) @db.Timestamp(6)
+  updated_at DateTime @default(now()) @db.Timestamp(6)
+
   Config Config[] @relation()
 
   @@map("users")