populate_db: Add a "lear" realm for testing cross-realm email sharing.

We don't yet actually allow sharing emails across realms, but we
will soon.  This lets us start testing some pieces of those changes.

zilencer/management/commands/populate_db.py

@@ -133,6 +133,10 @@ class Command(BaseCommand):
                     invite_required=False, org_type=Realm.CORPORATE)
                 RealmDomain.objects.create(realm=mit_realm, domain="mit.edu")
 
+                lear_realm = Realm.objects.create(
+                    string_id="lear", name="Lear & Co.", restricted_to_domain=False,
+                    invite_required=False, org_type=Realm.CORPORATE)
+
             # Create test Users (UserProfiles are automatically created,
             # as are subscriptions to the ability to receive personals).
             names = [
@@ -307,6 +311,11 @@ class Command(BaseCommand):
                 ]
                 create_users(mit_realm, testsuite_mit_users)
 
+                testsuite_lear_users = [
+                    ("King Lear", "king@lear.org"),
+                ]
+                create_users(lear_realm, testsuite_lear_users)
+
             if not options["test_suite"]:
                 # Initialize the email gateway bot as an API Super User
                 email_gateway_bot = get_system_bot(settings.EMAIL_GATEWAY_BOT)