feat: initial commit

cmd/migrate/migrations/000004_add_comments.up.sql

@@ -0,0 +1,10 @@
+CREATE TABLE IF NOT EXISTS Comments (
+    id  bigserial PRIMARY KEY,
+    post_id bigserial NOT NULL,
+    user_id bigserial NOT NULL,
+    content TEXT NOT NULL,
+    created_at timestamp(0) with time zone NOT NULL DEFAULT NOW(),
+    updated_at timestamp(0) with time zone NOT NULL DEFAULT NOW(),
+    FOREIGN KEY (post_id) REFERENCES Posts(id),
+    FOREIGN KEY (user_id) REFERENCES Users(id)
+);