diff --git a/app/controllers/graphql_controller.rb b/app/controllers/graphql_controller.rb
index c572322..9966435 100644
--- a/app/controllers/graphql_controller.rb
+++ b/app/controllers/graphql_controller.rb
@@ -1,13 +1,30 @@
 class GraphqlController < ApplicationController
+  before_action :authenticate
+
   def execute
     query_string = params[:query].to_s
     variables = ensure_hash(params[:variables])
-    result = ::Graph::Schema.execute(query_string, variables: variables)
+    context = {
+      user: @user
+    }
+
+    result = Graph::Schema.execute(query_string, variables: variables, context: context)
     render json: result
   end
 
   private
 
+  def authenticate
+    @user = authenticate_with_http_basic { |username, password|
+      user = User.where(username: username).first
+
+      return render plain: 'Invalid username', status: :unauthorized unless user
+      return render plain: 'Invalid password', status: :authorized unless user.authenticate(password)
+
+      user
+    }
+  end
+
   def ensure_hash(variables)
     if variables.blank?
       {}
diff --git a/app/models/graph/types/film.rb b/app/models/graph/types/film.rb
index 3f5d3a5..959537a 100644
--- a/app/models/graph/types/film.rb
+++ b/app/models/graph/types/film.rb
@@ -28,8 +28,11 @@ module Types
       field :releaseDate, !types.String,
         "The ISO 8601 date format of film release at original creator country.", property: :release_date
 
-      field :created_at, !types.String, "The ISO 8601 date format of the time that this resource was created."
-      field :updated_at, !types.String, "The ISO 8601 date format of the time that this resource was edited."
+      field :createdAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was created.", property: :created_at
+
+      field :updatedAt, !types.String, "The ISO 8601 date format of the time that this resource was edited.",
+        property: :updated_at
     end
   end
 end
diff --git a/app/models/graph/types/query.rb b/app/models/graph/types/query.rb
index 4f40483..53df069 100644
--- a/app/models/graph/types/query.rb
+++ b/app/models/graph/types/query.rb
@@ -46,6 +46,12 @@ module Types
         }
       end
 
+      field :viewer, Graph::Types::User, 'The currently authenticated user (if any)' do
+        resolve ->(_, _, ctx) {
+          ctx[:user]
+        }
+      end
+
       # Relay
       field :node, GraphQL::Relay::Node.field
       field :nodes, GraphQL::Relay::Node.plural_field
diff --git a/app/models/graph/types/species.rb b/app/models/graph/types/species.rb
index c86ef04..60de9ff 100644
--- a/app/models/graph/types/species.rb
+++ b/app/models/graph/types/species.rb
@@ -50,7 +50,7 @@ module Types
       end
 
       field :language, types.String, "The language commonly spoken by this species."
-      field :homeworld, Planet, "A planet that this species originates from type." do
+      field :homeworld, Graph::Types::Planet, "A planet that this species originates from type." do
         resolve -> (species, _, _) do
           Graph::AssociationLoader.for(::Species, :homeworld).load(species)
         end
diff --git a/app/models/graph/types/starship.rb b/app/models/graph/types/starship.rb
index ae36ebd..8e746df 100644
--- a/app/models/graph/types/starship.rb
+++ b/app/models/graph/types/starship.rb
@@ -53,8 +53,11 @@ module Types
       field :consumables, types.String, "The maximum length of time that this starship can provide consumables for its entire crew without having to resupply."
       connection :pilots, Graph::Types::Person.connection_type
 
-      field :created_at, !types.String, "The ISO 8601 date format of the time that this resource was created."
-      field :updated_at, !types.String, "The ISO 8601 date format of the time that this resource was updated."
+      field :createdAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was created.", property: :created_at
+
+      field :updatedAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was updated.", property: :updated_at
     end
   end
 end
diff --git a/app/models/graph/types/user.rb b/app/models/graph/types/user.rb
new file mode 100644
index 0000000..cf3e742
--- /dev/null
+++ b/app/models/graph/types/user.rb
@@ -0,0 +1,15 @@
+module Graph
+  module Types
+    User = GraphQL::ObjectType.define do
+      name "User"
+      description "A user that can rate films."
+
+      field :name, !types.String
+      field :username, !types.String
+      field :createdAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was created.", property: :created_at
+      field :updatedAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was updated.", property: :updated_at
+    end
+  end
+end
diff --git a/app/models/graph/types/vehicle.rb b/app/models/graph/types/vehicle.rb
index 53ed16c..cb973b6 100644
--- a/app/models/graph/types/vehicle.rb
+++ b/app/models/graph/types/vehicle.rb
@@ -39,8 +39,11 @@ module Types
       field :consumables, types.String, "The maximum length of time that this vehicle can provide consumables for its entire crew without having to resupply."
       connection :pilots, Graph::Types::Person.connection_type
 
-      field :created_at, !types.String, "The ISO 8601 date format of the time that this resource was created."
-      field :updated_at, !types.String, "The ISO 8601 date format of the time that this resource was updated."
+      field :createdAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was created.", property: :created_at
+
+      field :updatedAt, !types.String,
+        "The ISO 8601 date format of the time that this resource was updated.", property: :updated_at
     end
   end
 end
diff --git a/db/migrate/20170212223839_add_username_to_users.rb b/db/migrate/20170212223839_add_username_to_users.rb
new file mode 100644
index 0000000..9ca59f4
--- /dev/null
+++ b/db/migrate/20170212223839_add_username_to_users.rb
@@ -0,0 +1,8 @@
+class AddUsernameToUsers < ActiveRecord::Migration[5.0]
+  def change
+    change_table :users do |t|
+      t.string :username
+    end
+    add_index :users, :username, unique: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 6ea8d94..950678a 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170212195638) do
+ActiveRecord::Schema.define(version: 20170212223839) do
 
   create_table "films", force: :cascade do |t|
     t.string   "title"
@@ -153,6 +153,8 @@
     t.string   "password_digest"
     t.datetime "created_at",      null: false
     t.datetime "updated_at",      null: false
+    t.string   "username"
+    t.index ["username"], name: "index_users_on_username", unique: true
   end
 
   create_table "vehicles", force: :cascade do |t|
diff --git a/test/controllers/graphql_controller_test.rb b/test/controllers/graphql_controller_test.rb
index 1ca1af5..b580015 100644
--- a/test/controllers/graphql_controller_test.rb
+++ b/test/controllers/graphql_controller_test.rb
@@ -59,7 +59,7 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
           "cargoCapacity" => 100000.0,
           "consumables" => "2 months",
           "costInCredits" => 100000.0,
-          "created_at" => "2014-12-10 16:59:45 UTC",
+          "createdAt" => "2014-12-10 16:59:45 UTC",
           "crew" => "4",
           "hyperdriveRating" => 0.5,
           "length" => 34.37,
@@ -75,7 +75,7 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
           "cargoCapacity" => 10.0,
           "consumables" => "none",
           "costInCredits" => nil,
-          "created_at" => "2014-12-15 12:22:12 UTC",
+          "createdAt" => "2014-12-15 12:22:12 UTC",
           "crew" => "2",
           "length" => 4.5,
           "manufacturer" => "Incom corporation",
@@ -109,6 +109,50 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
     assert_equal expected, JSON.parse(response.body)
   end
 
+  test "#execute allows authentication via basic auth" do
+    query = """
+    {
+      viewer {
+        username
+      }
+    }
+"""
+
+    expected = {
+      "data" => {
+        "viewer" => {
+          "username" => "xuorig"
+        }
+      }
+    }
+
+    post graphql_url, params: { query: query }, headers: {
+      "Authorization" => ActionController::HttpAuthentication::Basic.encode_credentials("xuorig", "averysecurepassword"),
+    }
+
+    assert_equal expected, JSON.parse(response.body)
+  end
+
+  test "#execute authentication is not required" do
+    query = """
+    {
+      viewer {
+        username
+      }
+    }
+"""
+
+    expected = {
+      "data" => {
+        "viewer" => nil
+      }
+    }
+
+    post graphql_url, params: { query: query }
+
+    assert_equal expected, JSON.parse(response.body)
+  end
+
   private
 
   def full_graphql_query
@@ -167,7 +211,7 @@ def full_graphql_query
           cargoCapacity
           consumables
           costInCredits
-          created_at
+          createdAt
           crew
           hyperdriveRating
           length
@@ -183,7 +227,7 @@ def full_graphql_query
           cargoCapacity
           consumables
           costInCredits
-          created_at
+          createdAt
           crew
           length
           manufacturer
diff --git a/test/fixtures/users.yml b/test/fixtures/users.yml
index 0d210b9..c2466f3 100644
--- a/test/fixtures/users.yml
+++ b/test/fixtures/users.yml
@@ -1,3 +1,4 @@
-test-user:
-  name: xuorig
+xuorig:
+  name: Marc-André Giroux
+  username: xuorig
   password_digest: <%= BCrypt::Password.create('averysecurepassword', cost: BCrypt::Engine.cost) %>