Add an alias option to graphql container

[SachaG]

As explained in #354, your React component tree can get quite confusing when you have many nested Apollo(...) containers. This PR adds an alias option to the graphql HoC factory function:

options(ownProps) {
        return {
          alias: 'withCurrentUser',
        };
      },

Before:

After:

TODO:

• If this PR is a new feature, reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass
• Update CHANGELOG.md with your change
• If this was a change that affects the external API, update the docs and post a link to the PR in the discussion

[SachaG]

Also I wasn't sure where/how to write tests, so I thought I'd get feedback on the PR itself first and improve it later.

[tmeasday]

Can you write a test that just renders a aliased wrapped component and then checks it's display name?

[tmeasday]

I think it should be an OperationOption

[tmeasday]

If you make it an OperationOption (like name), you won't need to do this janky thing.

[jbaxleyiii]

This is awesome. I wonder if this can also be done with a babel transform which would be cool

[SachaG]

@tmeasday is that what you meant?

[tmeasday]

I don't think you need to do all this; it's sort of testing the query.metadata feature is working but there's a separate test for that (I assume).

Can you not just do

const instance = renderer.create(<Container>);
instance.displayName;

?

[SachaG]

I get an error: Invariant Violation: Could not find "client" in the context of "withFoo(Container)". Wrap the root component in an <ApolloProvider>.

But if I wrap the component in <ApolloProvider>, I'm not sure how to access its displayName…

[tmeasday]

Not sure what typescript is doing but Component.displayName is all we needed.

[SachaG]

Nice! Btw I meant to submit it as a separate PR, but I also added a short note in the README on how to work with the package locally, I thought it might help others.