migrations: add is_agent field

migrations.moon

@@ -20,4 +20,7 @@ import add_column, create_table, types from require "lapis.db.schema"
   [4]: =>
     add_column "users", "created_at", types.time
     add_column "users", "updated_at", types.time
+
+  [5]: =>
+    add_column "users", "is_agent", types.boolean
 }