init codebase

api/resources/migrations/007-create-channel-members.up.sql

@@ -0,0 +1,7 @@
+CREATE TABLE IF NOT EXISTS channel_members (
+  channel_id            uuid        NOT NULL REFERENCES channels (id) ON DELETE CASCADE,
+  user_id               uuid        NOT NULL REFERENCES users (id) ON DELETE CASCADE,
+  joined_at             timestamptz DEFAULT now(),
+  last_read_message_id  uuid,
+  PRIMARY KEY (channel_id, user_id)
+);