added superuser support in apps.lyric.admin & new manage.py cmd ensure_superuser; .tests.integrated.test_admin & .test_management_commands green

src/apps/lyric/admin.py

@@ -1,6 +1,11 @@
 from django.contrib import admin
+
 from .models import Token, User
 
 
-admin.site.register(User)
+class UserAdmin(admin.ModelAdmin):
+    list_display = ["email"]
+    search_fields = ["email"]
+
+admin.site.register(User, UserAdmin)
 admin.site.register(Token)