add subjects and reviwers query

app/graphql/resolvers/reviewers_query_resolver.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+module Resolvers
+  class ReviewersQueryResolver
+    def initialize(context)
+      @context = context
+    end
+
+    def resolve
+      UserPolicy::Scope.new(@context[:current_user], User)
+        .resolve
+        .joins(:roles)
+        .where(roles: { name: %i[teacher nde] })
+        .where.not(id: @context[:current_user].id)
+        .distinct
+    end
+  end
+end

app/graphql/resolvers/subjects_query_resolver.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+module Resolvers
+  class SubjectsQueryResolver
+    def initialize(context)
+      @context = context
+    end
+
+    def resolve
+      SubjectPolicy::Scope.new(@context[:current_user], Subject).resolve
+    end
+  end
+end

app/graphql/sources/active_record.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Sources
+  class ActiveRecord < GraphQL::Dataloader::Source
+    def initialize(model_class)
+      @model_class = model_class
+    end
+
+    def fetch(ids)
+      records = @model_class.where(id: ids).index_by(&:id)
+      records.slice(*ids).values
+    end
+  end
+end

app/graphql/types/axis_type.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Types
+  class AxisType < Types::BaseObject
+    field :id, ID, null: false
+    field :name, String, null: false
+    field :subjects, [SubjectType], null: false
+  end
+end

app/graphql/types/category_type.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Types
+  class CategoryType < Types::BaseObject
+    field :id, ID, null: false
+    field :name, String, null: false
+    field :subjects, [SubjectType], null: false
+  end
+end

app/graphql/types/query_type.rb

@@ -1,19 +1,27 @@
 module Types
   class QueryType < Types::BaseObject
-    # Add `node(id: ID!) and `nodes(ids: [ID!]!)`
     include GraphQL::Types::Relay::HasNodeField
     include GraphQL::Types::Relay::HasNodesField
 
     field :questions, QuestionType.connection_type, null: false do
       argument :where, Inputs::QuestionWhereInput, required: false
     end
-
+    field :subjects, SubjectType.connection_type, null: false
+    field :reviewers, UserType.connection_type, null: false
     field :current_user, Types::UserType, null: true
 
     def questions(where: nil)
       Resolvers::QuestionsQueryResolver.new(Question, context: context, where: where).resolve
     end
 
+    def subjects
+      Resolvers::SubjectsQueryResolver.new(context).resolve
+    end
+
+    def reviewers
+      Resolvers::ReviewersQueryResolver.new(context).resolve
+    end
+
     def current_user
       context[:current_user]
     end

app/graphql/types/subject_type.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Types
+  class SubjectType < Types::BaseObject
+    field :id, ID, null: false
+    field :name, String, null: false
+
+    field :axis, AxisType, null: false
+    def axis
+      dataloader.with(Sources::ActiveRecord, Axis).load(object.axis_id)
+    end
+
+    field :category, CategoryType, null: false
+    def category
+      dataloader.with(Sources::ActiveRecord, Category).load(object.category_id)
+    end
+
+    field :questions, QuestionType.connection_type, null: false do
+      argument :where, Inputs::QuestionWhereInput, required: false
+    end
+    def questions(where: nil)
+      Resolvers::QuestionsQueryResolver.new(object.questions, context: context, where: where).resolve
+    end
+  end
+end