(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/Alias.ts

@@ -0,0 +1,27 @@
+import {BaseEntity, Column, CreateDateColumn, Entity, JoinColumn, ManyToOne,
+        PrimaryColumn} from 'typeorm';
+import {Document} from './Document';
+import {Organization} from './Organization';
+
+@Entity({name: 'aliases'})
+export class Alias extends BaseEntity {
+  @PrimaryColumn({name: 'org_id'})
+  public orgId: number;
+
+  @PrimaryColumn({name: 'url_id'})
+  public urlId: string;
+
+  @Column({name: 'doc_id'})
+  public docId: string;
+
+  @ManyToOne(type => Document)
+  @JoinColumn({name: 'doc_id'})
+  public doc: Document;
+
+  @ManyToOne(type => Organization)
+  @JoinColumn({name: 'org_id'})
+  public org: Organization;
+
+  @CreateDateColumn({name: 'created_at'})
+  public createdAt: Date;
+}