collab: Add separate billing_customers table (#15457)

This PR adds a new `billing_customers` table to hold the billing
customers.

Previously we were storing both the `stripe_customer_id` and
`stripe_subscription_id` in the `billable_subscriptions` table. However,
this creates problems when we need to correlate subscription events back
to the subscription record, as we don't know the user that the Stripe
event corresponds to.

By moving the `stripe_customer_id` to a separate table we can create the
Stripe customer earlier in the flow—before we create the Stripe Checkout
session—and associate that customer with a user. This way when we
receive events down the line we can use the Stripe customer ID to
correlate it back to the user.

We're doing some destructive actions to the `billing_subscriptions`
table, but this is fine, as we haven't started using them yet.

Release Notes:

- N/A

crates/collab/src/db/tables/billing_customer.rs

@@ -0,0 +1,39 @@
+use crate::db::{BillingCustomerId, UserId};
+use sea_orm::entity::prelude::*;
+
+/// A billing customer.
+#[derive(Clone, Debug, Default, PartialEq, Eq, DeriveEntityModel)]
+#[sea_orm(table_name = "billing_customers")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: BillingCustomerId,
+    pub user_id: UserId,
+    pub stripe_customer_id: String,
+    pub created_at: DateTime,
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::UserId",
+        to = "super::user::Column::Id"
+    )]
+    User,
+    #[sea_orm(has_many = "super::billing_subscription::Entity")]
+    BillingSubscription,
+}
+
+impl Related<super::user::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::User.def()
+    }
+}
+
+impl Related<super::billing_subscription::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::BillingSubscription.def()
+    }
+}
+
+impl ActiveModelBehavior for ActiveModel {}

crates/collab/src/db/tables/billing_subscription.rs

@@ -1,4 +1,4 @@
-use crate::db::{BillingSubscriptionId, UserId};
+use crate::db::{BillingCustomerId, BillingSubscriptionId};
 use sea_orm::entity::prelude::*;
 
 /// A billing subscription.
@@ -7,8 +7,7 @@ use sea_orm::entity::prelude::*;
 pub struct Model {
     #[sea_orm(primary_key)]
     pub id: BillingSubscriptionId,
-    pub user_id: UserId,
-    pub stripe_customer_id: String,
+    pub billing_customer_id: BillingCustomerId,
     pub stripe_subscription_id: String,
     pub stripe_subscription_status: StripeSubscriptionStatus,
     pub created_at: DateTime,
@@ -17,16 +16,16 @@ pub struct Model {
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
 pub enum Relation {
     #[sea_orm(
-        belongs_to = "super::user::Entity",
-        from = "Column::UserId",
-        to = "super::user::Column::Id"
+        belongs_to = "super::billing_customer::Entity",
+        from = "Column::BillingCustomerId",
+        to = "super::billing_customer::Column::Id"
     )]
-    User,
+    BillingCustomer,
 }
 
-impl Related<super::user::Entity> for Entity {
+impl Related<super::billing_customer::Entity> for Entity {
     fn to() -> RelationDef {
-        Relation::User.def()
+        Relation::BillingCustomer.def()
     }
 }
 

crates/collab/src/db/tables/user.rs

@@ -24,8 +24,8 @@ pub struct Model {
 pub enum Relation {
     #[sea_orm(has_many = "super::access_token::Entity")]
     AccessToken,
-    #[sea_orm(has_many = "super::billing_subscription::Entity")]
-    BillingSubscription,
+    #[sea_orm(has_one = "super::billing_customer::Entity")]
+    BillingCustomer,
     #[sea_orm(has_one = "super::room_participant::Entity")]
     RoomParticipant,
     #[sea_orm(has_many = "super::project::Entity")]
@@ -44,6 +44,12 @@ impl Related<super::access_token::Entity> for Entity {
     }
 }
 
+impl Related<super::billing_customer::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::BillingCustomer.def()
+    }
+}
+
 impl Related<super::room_participant::Entity> for Entity {
     fn to() -> RelationDef {
         Relation::RoomParticipant.def()