Name model for usernames (#265)

* Create Name model for usernames
* SQLAlchemy supports functional indexes now. Also make `name`'s uniqueness case-insensitive.
* Unit tests for Name model
* Change username length to 63 (DNS limit)
* Add `name` hybrid property and fix form validation
* Fix PostgreSQL indexing pattern. Undo error introduced in Alembic revision 3b17b62bf8e4

features/steps/failed_registration.py

@@ -40,5 +40,5 @@ def when_form_submit(context):
 @then('the new user will not be registered')
 def then_user_registered(context):
     # just one user exists, the first one
-    user_query = User.query.filter_by(username=context.test_user['username'])
-    assert user_query.count() == 1
+    user = User.get(username=context.test_user['username'])
+    assert user is not None

lastuser_core/models/__init__.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
-from coaster.sqlalchemy import TimestampMixin, BaseMixin, BaseScopedNameMixin, UuidMixin  # Imported from here by other models  # NOQA
+# Imported from here by other models
+from coaster.sqlalchemy import TimestampMixin, BaseMixin, BaseScopedNameMixin, UuidMixin  # NOQA
 from coaster.db import db
 
 
@@ -47,7 +48,13 @@ def merge_users(user1, user2):
     else:
         keep_user, merge_user = user2, user1
 
-    # 1. Inspect all tables for foreign key references to merge_user and switch to keep_user.
+    # 1. Release the username
+    if not keep_user.username:
+        if merge_user.username:
+            keep_user.username = merge_user.username
+    merge_user.username = None
+
+    # 2. Inspect all tables for foreign key references to merge_user and switch to keep_user.
     for model in db.Model.__subclasses__():
         if model != User:
             # a. This is a model and it's not the User model. Does it have a migrate_user classmethod?
@@ -57,12 +64,10 @@ def merge_users(user1, user2):
             elif hasattr(model, 'user_id') and hasattr(model, 'query'):
                 for row in model.query.filter_by(user_id=merge_user.id).all():
                     row.user_id = keep_user.id
-    # 2. Add merge_user's uuid to olduserids. Commit session.
+    # 3. Add merge_user's uuid to olduserids. Commit session.
     db.session.add(UserOldId(id=merge_user.uuid, user=keep_user))
-    # 3. Mark merge_user as merged. Commit session.
+    # 4. Mark merge_user as merged. Commit session.
     merge_user.status = USER_STATUS.MERGED
-    # 4. Release the username
-    merge_user.username = None
     # 5. Commit all of this
     db.session.commit()