feat(project) add refresh.sh

backend/post.sql

@@ -1,4 +1,4 @@
-CREATE TABLE Post
+CREATE TABLE IF NOT EXISTS Post
 (
     post_id     UUID PRIMARY KEY,
     title       VARCHAR(255) NOT NULL,

backend/tag.sql

@@ -1,4 +1,4 @@
-CREATE TABLE Tag
+CREATE TABLE IF NOT EXISTS Tag
 (
     post_id UUID         NOT NULL,
     tag     VARCHAR(255) NOT NULL