Add a Link type & the allLinks resolver

app/graphql/graphql_tutorial_schema.rb

@@ -1,4 +1,4 @@
 GraphqlTutorialSchema = GraphQL::Schema.define do
-  mutation(Types::MutationType)
+  # mutation(Types::MutationType)
   query(Types::QueryType)
 end

app/graphql/types/link_type.rb

@@ -0,0 +1,7 @@
+Types::LinkType = GraphQL::ObjectType.define do
+  name 'Link'
+
+  field :id, !types.ID
+  field :url, !types.String
+  field :description, !types.String
+end

app/graphql/types/query_type.rb

@@ -3,11 +3,7 @@
   # Add root-level fields here.
   # They will be entry points for queries on your schema.
 
-  # TODO: remove me
-  field :testField, types.String do
-    description "An example field added by the generator"
-    resolve ->(obj, args, ctx) {
-      "Hello World!"
-    }
+  field :allLinks, !types[Types::LinkType] do
+    resolve -> (obj, args, ctx) { Link.all }
   end
 end