Merge pull request #92 from graphql-go/graphql-playground-endpoint-su…

…pport

Adds support for setting GraphQL Playground endpoints.

Merge pull request #61 from monmaru/fixed-endpoint-embedded-in-template

Fixed the endpoint embedded in the playground's html template

Merge pull request #52 from michurin/cosmetics

Cosmetics

Merge pull request #29 from graphql-go/fix/variables-bug

handler: fixes queryparams variables

Merge pull request #26 from mastertinner/feature/graphiql

Add GraphiQL support

Merge pull request #19 from arthurnn/patch-1

fix readme [skip ci]