init commit

store/migration/sqlite/0.20/00__reaction.sql

@@ -0,0 +1,9 @@
+-- reaction
+CREATE TABLE reaction (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  created_ts BIGINT NOT NULL DEFAULT (strftime('%s', 'now')),
+  creator_id INTEGER NOT NULL,
+  content_id TEXT NOT NULL,
+  reaction_type TEXT NOT NULL,
+  UNIQUE(creator_id, content_id, reaction_type)
+);