(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/User.ts

@@ -0,0 +1,54 @@
+import {BaseEntity, Column, Entity, JoinTable, ManyToMany, OneToMany, OneToOne,
+        PrimaryGeneratedColumn} from "typeorm";
+
+import {Group} from "./Group";
+import {Login} from "./Login";
+import {Organization} from "./Organization";
+
+@Entity({name: 'users'})
+export class User extends BaseEntity {
+
+  @PrimaryGeneratedColumn()
+  public id: number;
+
+  @Column()
+  public name: string;
+
+  @Column({name: 'api_key', type: String, nullable: true})
+  // Found how to make a type nullable in this discussion: https://github.com/typeorm/typeorm/issues/2567
+  // todo: adds constraint for api_key not to equal ''
+  public apiKey: string | null;
+
+  @Column({name: 'picture', type: String, nullable: true})
+  public picture: string | null;
+
+  @Column({name: 'first_login_at', type: Date, nullable: true})
+  public firstLoginAt: Date | null;
+
+  @OneToOne(type => Organization, organization => organization.owner)
+  public personalOrg: Organization;
+
+  @OneToMany(type => Login, login => login.user)
+  public logins: Login[];
+
+  @ManyToMany(type => Group)
+  @JoinTable({
+    name: 'group_users',
+    joinColumn: {name: 'user_id'},
+    inverseJoinColumn: {name: 'group_id'}
+  })
+  public groups: Group[];
+
+  @Column({name: 'is_first_time_user', default: false})
+  public isFirstTimeUser: boolean;
+
+  /**
+   * Get user's email.  Returns undefined if logins has not been joined, or no login
+   * is available
+   */
+  public get loginEmail(): string|undefined {
+    const login = this.logins && this.logins[0];
+    if (!login) { return undefined; }
+    return login.email;
+  }
+}