implement first draft of switching handoperatable boats

staging-diff.sql

@@ -1,3 +1,6 @@
+ALTER TABLE boat ADD COLUMN convert_handoperated_possible BOOLEAN DEFAULT false NOT NULL;
+
+
 -- test user
 INSERT INTO user(name) VALUES('Marie');
 INSERT INTO "user_role" (user_id, role_id) VALUES((SELECT id from user where name = 'Marie'),(SELECT id FROM role where name = 'Donau Linz'));