feat(page): page and section backend

ee/tabby-db/migrations/0042_page-section.down.sql

@@ -0,0 +1,2 @@
+DROP TABLE page_sections;
+DROP TABLE pages;

ee/tabby-db/migrations/0042_page-section.up.sql

@@ -0,0 +1,42 @@
+CREATE TABLE pages(
+    id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+
+    -- Whether the page is draft
+    is_draft BOOLEAN NOT NULL,
+
+    -- The user who created the page
+    user_id INTEGER NOT NULL,
+
+    -- Array of relevant questions, in format of `String`
+    relevant_questions BLOB,
+
+    created_at TIMESTAMP NOT NULL DEFAULT (DATETIME('now')),
+    updated_at TIMESTAMP NOT NULL DEFAULT (DATETIME('now')),
+
+    FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+
+CREATE TABLE page_sections(
+    id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    page_id INTEGER NOT NULL,
+
+    order_index INTEGER NOT NULL,
+
+    title TEXT NOT NULL,
+    content TEXT NOT NULL,
+
+    -- TODO: link or updated image
+    media BLOB,
+
+    -- TODO: user input source
+    client_sources BLOB,
+
+    -- TODO: json format
+    sources BLOB,
+
+    created_at TIMESTAMP NOT NULL DEFAULT (DATETIME('now')),
+    updated_at TIMESTAMP NOT NULL DEFAULT (DATETIME('now')),
+
+    FOREIGN KEY(thread_id) REFERENCES threads(id) ON DELETE CASCADE,
+    CONSTRAINT `page_id_order_index` UNIQUE(page_id, order_index)
+);