Done

lib/appointment.rb

@@ -0,0 +1,16 @@
+class Appointment
+    attr_accessor :date, :doctor, :patient
+
+    @@all = []
+
+    def initialize(date, patient, doctor)
+      @date = date
+      @doctor = doctor
+      @patient = patient
+      @@all << self
+    end
+
+    def self.all
+      @@all
+    end
+  end

lib/artist.rb

@@ -0,0 +1,29 @@
+class Artist
+    attr_accessor :name, :genres, :songs
+    @@all = []
+
+    def initialize(name)
+        @name = name
+        @@all << self
+    end
+
+    def new_song(name, genre)
+        Song.new(name, self, genre)
+    end
+
+    def songs
+        Song.all.select do |song|
+            song.artist == self
+        end
+    end
+
+    def genres
+        self.songs.collect do |song|
+            song.genre
+        end
+    end
+
+    def self.all
+        @@all
+    end
+end

lib/doctor.rb

@@ -0,0 +1,29 @@
+class Doctor
+    attr_accessor :name, :appointments, :patients
+    @@all = []
+
+    def initialize(name)
+      @name = name
+      @@all << self
+    end
+
+    def self.all
+      @@all
+    end
+
+    def new_appointment(patient, date)
+      Appointment.new(date, patient, self)
+    end
+
+    def appointments
+      Appointment.all.select do |appointment|
+        appointment.doctor == self
+      end
+    end
+
+    def patients
+        self.appointments.collect do |appointment|
+            appointment.patient
+        end
+    end
+end

lib/genre.rb

@@ -0,0 +1,25 @@
+class Genre
+    attr_accessor :name, :artists, :songs
+    @@all = []
+
+    def initialize(name)
+        @name = name
+        @@all << self
+    end
+
+    def songs
+        Song.all.select do |song|
+            song.genre == self
+        end
+    end
+
+    def artists
+        self.songs.collect do |song|
+            song.artist
+        end
+    end
+
+    def self.all
+        @@all
+    end
+end

lib/patient.rb

@@ -0,0 +1,29 @@
+class Patient
+    attr_accessor :name, :appointments, :doctors
+    @@all = []
+
+    def initialize(name)
+      @name = name
+      @@all << self
+    end
+
+    def self.all
+      @@all
+    end
+
+    def new_appointment(doctor, date)
+      Appointment.new(date, self, doctor)
+    end
+
+    def appointments
+      Appointment.all.select do |appointment|
+        appointment.patient == self
+      end
+    end
+
+    def doctors
+        self.appointments.collect do |appointment|
+            appointment.doctor
+        end
+    end
+  end

lib/song.rb

@@ -0,0 +1,15 @@
+class Song
+   attr_accessor :name, :artist, :genre
+   @@all = []
+
+   def initialize(name, artist, genre)
+    @name = name
+    @artist = artist
+    @genre = genre
+    @@all << self
+   end
+
+   def self.all
+    @@all
+   end
+end

spec/01_artist_spec.rb

@@ -1,6 +1,5 @@
 require "spec_helper"
 
-
 describe "Artist" do
 
   describe "#name" do