feat: create words table #be

backend/migrations/20220309170000_pgcrypto.ts

+import { Knex } from "knex";
+
+export async function up(knex: Knex): Promise<void> {
+  return knex.schema.raw('CREATE EXTENSION IF NOT EXISTS "pgcrypto"');
+}
+
+export async function down(knex: Knex): Promise<void> {
+  return knex.schema.raw('DROP EXTENSION IF EXISTS "pgcrypto"');
+}

backend/migrations/20220309170943_words.ts

+import { Knex } from "knex";
+
+export async function up(knex: Knex): Promise<void> {
+  return knex.schema.createTable("words", function (table) {
+    table.uuid("id").primary().defaultTo(knex.raw("gen_random_uuid()"));
+    table.string("page_id").index().notNullable();
+    table.integer("word_id").index().notNullable();
+    table.unique(["page_id", "word_id"]);
+    table.binary("image").notNullable();
+    table.string("ocr_transcript");
+    table.float("ocr_confidence");
+  });
+}
+
+export async function down(knex: Knex): Promise<void> {
+  return knex.schema.dropTable("words");
+}