Bundle external JavaScript sources for GraphiQL

[tvogels]

Currently, the GraphiQL interface served with graphene-django cannot be used without an internet connection because it relies on javascript files served from a CDN. This can be problematic in some dev environments. I would suggest bundling these files instead to ensure graphiql can also be used offline.

[zbyte64]

This could make #498 obsolete

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[eoinof]

For anyone who encounters this you can pretty easily specify a custom template file.
e.g. in your urls file

GraphQLView.graphiql_template = 'graphql/customGraphiQL.html

graph_urls = [
url(r'^graphql', GraphQLView.as_view(graphiql=settings.DEBUG)),
]
`