Js-graphql-intellij-plugin: support graphcool framework

[smmoosavi]

in graphcool framework we can see @model, @isUnique in schema file. which not supported with graphql plugin

https://github.com/graphcool/framework

# The following types define the data model of the example service
# based on which the GraphQL API is generated

type User @model {
  id: ID! @isUnique
  name: String!
  dateOfBirth: DateTime

  # Uncomment below - you can declare relations between models like this

  # posts: [Post!]! @relation(name: "UserPosts")
}


# Uncomment the model below as well

# type Post @model {
#   id: ID! @isUnique
#   title: String!
# 
#   # Every relation also required a back-relation (to determine 1:1, 1:n or n:m)
#   author: User! @relation(name: "UserPosts")
# }

[smmoosavi]

maybe this link can help: https://www.graph.cool/docs/reference/database/data-modelling-eiroozae8u/#graphql-directives

[flux627]

Maybe the ability to add arbitrary white-listed directives to configuration would be a catch-all solution for things like this.

[jimkyndemeyer]

I'm merging this and related issues into #121