(core) move home server into core

Summary: This moves enough server material into core to run a home server.  The data engine is not yet incorporated (though in manual testing it works when ported).

Test Plan: existing tests pass

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2552

app/gen-server/entity/BillingAccount.ts

@@ -0,0 +1,65 @@
+import {BaseEntity, Column, Entity, JoinColumn, ManyToOne, OneToMany, PrimaryGeneratedColumn} from 'typeorm';
+import {BillingAccountManager} from 'app/gen-server/entity/BillingAccountManager';
+import {Organization} from 'app/gen-server/entity/Organization';
+import {Product} from 'app/gen-server/entity/Product';
+import {nativeValues} from 'app/gen-server/lib/values';
+
+// This type is for billing account status information.  Intended for stuff
+// like "free trial running out in N days".
+interface BillingAccountStatus {
+  stripeStatus?: string;
+  currentPeriodEnd?: Date;
+  message?: string;
+}
+
+/**
+ * This relates organizations to products.  It holds any stripe information
+ * needed to be able to update and pay for the product that applies to the
+ * organization.  It has a list of managers detailing which users have the
+ * right to view and edit these settings.
+ */
+@Entity({name: 'billing_accounts'})
+export class BillingAccount extends BaseEntity {
+  @PrimaryGeneratedColumn()
+  public id: number;
+
+  @ManyToOne(type => Product)
+  @JoinColumn({name: 'product_id'})
+  public product: Product;
+
+  @Column()
+  public individual: boolean;
+
+  // A flag for when all is well with the user's subscription.
+  // Probably shouldn't use this to drive whether service is provided or not.
+  // Strip recommends updating an end-of-service datetime every time payment
+  // is received, adding on a grace period of some days.
+  @Column({name: 'in_good_standing', default: nativeValues.trueValue})
+  public inGoodStanding: boolean;
+
+  @Column({type: nativeValues.jsonEntityType, nullable: true})
+  public status: BillingAccountStatus;
+
+  @Column({name: 'stripe_customer_id', type: String, nullable: true})
+  public stripeCustomerId: string | null;
+
+  @Column({name: 'stripe_subscription_id', type: String, nullable: true})
+  public stripeSubscriptionId: string | null;
+
+  @Column({name: 'stripe_plan_id', type: String, nullable: true})
+  public stripePlanId: string | null;
+
+  @OneToMany(type => BillingAccountManager, manager => manager.billingAccount)
+  public managers: BillingAccountManager[];
+
+  @OneToMany(type => Organization, org => org.billingAccount)
+  public orgs: Organization[];
+
+  // A calculated column that is true if it looks like there is a paid plan.
+  @Column({name: 'paid', type: 'boolean', insert: false, select: false})
+  public paid?: boolean;
+
+  // A calculated column summarizing whether active user is a manager of the billing account.
+  // (No @Column needed since calculation is done in javascript not sql)
+  public isManager?: boolean;
+}