build: gallery domain의 flyway ddl을 작성한다

api/src/main/resources/db/migration/V7__gallery.sql

@@ -0,0 +1,28 @@
+create table if not exists gallery(
+       id bigint not null,
+       created_at TIMESTAMP(6) not null,
+       updated_at TIMESTAMP(6) not null,
+       feedback_reply varchar(255),
+       feedback_count integer not null,
+       survey_id bigint not null unique,
+       save_count integer not null,
+       user_id bigint not null unique,
+       user_name varchar(255) not null,
+       user_nickname varchar(255) not null,
+       user_image_url varchar(255),
+       version bigint,
+       primary key (id)
+);
+
+create index gallery_idx_user_id on gallery(user_id);
+
+create table gallery_survey_tendency(
+       id bigint not null,
+       tendency_name varchar(255),
+       tendency_count integer
+);
+
+alter table gallery_survey_tendency
+add constraint gallery_fk_gallery_survey_tendency
+foreign key (id) references gallery(id);
+