Made some changes to how index pages are made

sql/schema/1_init.up.sql

@@ -17,6 +17,10 @@ CREATE TYPE page_name_provenance AS ENUM (
     'date'
 );
 
+CREATE TYPE page_role AS ENUM (
+    'index'
+);
+
 CREATE TABLE users (
     id       BIGSERIAL NOT NULL PRIMARY KEY,
     email    TEXT      NOT NULL UNIQUE,
@@ -36,7 +40,7 @@ CREATE TABLE sites (
 
 -- Post role is used to describe a specific kind of post, such as a link.
 -- When set, it specifies the layout to use for the page
-CREATE TABLE post_roles (
+CREATE TABLE post_types (
     id          BIGSERIAL NOT NULL PRIMARY KEY,
     site_id     BIGINT    NOT NULL,
     layout_name TEXT      NOT NULL,
@@ -48,7 +52,7 @@ CREATE TABLE posts (
     id           BIGSERIAL  NOT NULL PRIMARY KEY,
     site_id      BIGINT     NOT NULL,
     title        TEXT,
-    role         BIGINT,
+    post_type_id BIGINT,
     body         TEXT       NOT NULL,
     state        post_state NOT NULL,
     props        JSON       NOT NULL,
@@ -56,7 +60,7 @@ CREATE TABLE posts (
     created_at   TIMESTAMP  NOT NULL,
     updated_at   TIMESTAMP  NOT NULL,
 
-    FOREIGN KEY (role) REFERENCES post_roles (id) ON DELETE CASCADE,
+    FOREIGN KEY (post_type_id) REFERENCES post_types (id) ON DELETE CASCADE,
     FOREIGN KEY (site_id) REFERENCES sites (id) ON DELETE CASCADE
 );
 
@@ -77,19 +81,21 @@ CREATE TABLE pages (
     name            TEXT                 NOT NULL,
     name_provenance page_name_provenance NOT NULL,
     title           TEXT,
-    role            BIGINT,
+    post_type_id    BIGINT,
     body            TEXT                 NOT NULL,
     state           post_state           NOT NULL,
     props           JSON                 NOT NULL,
+    role            page_role,
     publish_date    TIMESTAMP WITH TIME ZONE,
     created_at      TIMESTAMP            NOT NULL,
     updated_at      TIMESTAMP            NOT NULL,
 
     UNIQUE (bundle_id, name),
     FOREIGN KEY (site_id) REFERENCES sites (id) ON DELETE CASCADE,
-    FOREIGN KEY (role) REFERENCES post_roles (id) ON DELETE CASCADE,
+    FOREIGN KEY (post_type_id) REFERENCES post_types (id) ON DELETE CASCADE,
     FOREIGN KEY (bundle_id) REFERENCES sites (id) ON DELETE CASCADE
 );
+CREATE UNIQUE INDEX page_bundle_id_role ON pages (bundle_id, role) WHERE (role is NOT null);
 
 CREATE TABLE publish_targets (
     id          BIGSERIAL   NOT NULL PRIMARY KEY,