Upgrade Peewee to latest 3.x

This requires a number of small changes in the data model code, as well as additional testing.

initdb.py

@@ -7,8 +7,7 @@ import os
 import argparse
 
 from datetime import datetime, timedelta, date
-from peewee import (SqliteDatabase, create_model_tables, drop_model_tables, savepoint_sqlite,
-                    savepoint)
+from peewee import SqliteDatabase
 from itertools import count
 from uuid import UUID, uuid4
 from threading import Event
@@ -210,6 +209,7 @@ def finished_database_for_testing(testcase):
       any changes should be discarded.
   """
   testcases[testcase]['savepoint'].__exit__(True, None, None)
+  testcases[testcase]['atomic'].__exit__(True, None, None)
 
 def setup_database_for_testing(testcase, with_storage=False, force_rebuild=False):
   """ Called when a testcase has started using the database, indicating that
@@ -242,15 +242,16 @@ def setup_database_for_testing(testcase, with_storage=False, force_rebuild=False
     db_initialized_for_testing.set()
 
   # Create a savepoint for the testcase.
-  test_savepoint = savepoint(db) if IS_TESTING_REAL_DATABASE else savepoint_sqlite(db)
-
   testcases[testcase] = {}
-  testcases[testcase]['savepoint'] = test_savepoint
+  testcases[testcase]['atomic'] = db.manual_commit()
+  testcases[testcase]['atomic'].__enter__()
+
+  testcases[testcase]['savepoint'] = db.savepoint()
   testcases[testcase]['savepoint'].__enter__()
 
 
 def initialize_database():
-  create_model_tables(all_models)
+  db.create_tables(all_models)
 
   Role.create(name='admin')
   Role.create(name='write')
@@ -447,7 +448,7 @@ def wipe_database():
   if not IS_TESTING_REAL_DATABASE and not isinstance(db.obj, SqliteDatabase):
     raise RuntimeError('Attempted to wipe production database!')
 
-  drop_model_tables(all_models, fail_silently=True)
+  db.drop_tables(all_models)
 
 
 def populate_database(minimal=False, with_storage=False):