tsk-57: Change schema of scheduled_message_events (#65)

Closes #57

Reviewed-on: phoenix/textsender-api#65
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

migrations/schema.sql

@@ -28,7 +28,7 @@ CREATE TABLE IF NOT EXISTS scheduled_messages (
 
 CREATE TABLE IF NOT EXISTS scheduled_message_events (
     id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
-    recipient_id UUID NOT NULL,
+    contact_id UUID NOT NULL,
     message_id UUID NOT NULL,
     scheduled_message_id UUID NOT NULL,
     created timestamptz DEFAULT now()