Add SDL for rest directive

[jasonpaulos]

Since version 1.10.0 of the Apollo VS Code extension, which by default requires definitions for all directives, I believe apollo-link-rest should provide a schema definition for the @rest directive. This definition can then be used as follows in the apollo.config.js file that the VS Code extension reads:

var apolloRestSchema = require.resolve('apollo-link-rest/schema.graphql');

module.exports = {
  client: {
    name: 'Space Explorer [web]',
    service: 'apollographql-8341',
    includes: [
      'src/**/*.{ts,tsx,js,jsx,graphql,gql}',
      apolloRestSchema
    ]
  }
};

This will allow developers to validate their use of directives and provide many IntelliSense features, such as autocompletion and argument information on hover for directives. A history of the relevant VS Code changes can be found here: apollographql/apollo-tooling#1433

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Here is a similar PR for apollo-client: apollographql/apollo-client#5205

[codecov-io]

Codecov Report

Merging #228 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #228   +/-   ##
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  Coverage   92.71%   92.71%           
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  Files           3        3           
  Lines         412      412           
  Branches      123      123           
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  Hits          382      382           
  Misses         28       28           
  Partials        2        2

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[fbartho]

I have no problem adding this schema.graphql file into our exports. Thanks for figuring all that out!

Does this mean apollo-cli code generation will also understand the @rest(…) directive going forwards?

Additional question, if a user is using: apollo-link-rest, local state through resolvers, and an ApolloServer backend, how should they configure their apollo.config.js file?
-- Relatedly, should we add your example apollo.config.js entries into the links/rest docs? (https://github.com/apollographql/apollo-link-rest/tree/master/docs mirroring the content from: https://github.com/apollographql/apollo-link/tree/master/docs/source/links/rest.md rendered at https://www.apollographql.com/docs/link/links/rest.html)

Are there any useful unit tests that we can apply here?

[fbartho]

Published under: https://github.com/apollographql/apollo-link-rest/releases/tag/v0.8.0-beta.0