Update graphql README.md
`go mod init github.com/[username]/gqlgen-todos`
- install gqlgen
`go get github.com/99designs/gqlgen`
-- replace with arsmn/gqlgen by adding this line in go.mod file
+- replace with arsmn/gqlgen by adding this line in go.mod file <br/>
`replace github.com/99designs/gqlgen v0.13.0 => github.com/arsmn/gqlgen v0.13.2`
- build the server
`go run github.com/99designs/gqlgen init`
- implement the resolvers
- run the server
`go run server.go`
+- browse `http://localhost:8080/` for playground
- see more [examples](https://github.com/arsmn/gqlgen/tree/master/example) and [documentation](https://gqlgen.com)
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