Upgrade Peewee to latest 3.x

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

test/fixtures.py

@@ -8,7 +8,7 @@ from flask import Flask, jsonify
 from flask_login import LoginManager
 from flask_principal import identity_loaded, Permission, Identity, identity_changed, Principal
 from flask_mail import Mail
-from peewee import SqliteDatabase, savepoint, InternalError
+from peewee import SqliteDatabase, InternalError
 
 from app import app as application
 from auth.permissions import on_identity_loaded
@@ -147,19 +147,20 @@ def initialized_db(appconfig):
   # If under a test *real* database, setup a savepoint.
   under_test_real_database = bool(os.environ.get('TEST_DATABASE_URI'))
   if under_test_real_database:
-    test_savepoint = savepoint(db)
-    test_savepoint.__enter__()
+    with db.transaction():
+      test_savepoint = db.savepoint()
+      test_savepoint.__enter__()
 
-    yield # Run the test.
+      yield # Run the test.
 
-    try:
-      test_savepoint.rollback()
-      test_savepoint.__exit__(None, None, None)
-    except InternalError:
-      # If postgres fails with an exception (like IntegrityError) mid-transaction, it terminates
-      # it immediately, so when we go to remove the savepoint, it complains. We can safely ignore
-      # this case.
-      pass
+      try:
+        test_savepoint.rollback()
+        test_savepoint.__exit__(None, None, None)
+      except InternalError:
+        # If postgres fails with an exception (like IntegrityError) mid-transaction, it terminates
+        # it immediately, so when we go to remove the savepoint, it complains. We can safely ignore
+        # this case.
+        pass
   else:
     yield