diff --git a/lib/jam_ruby.rb b/lib/jam_ruby.rb
index f886f77ad..55d61a0ea 100644
--- a/lib/jam_ruby.rb
+++ b/lib/jam_ruby.rb
@@ -10,6 +10,7 @@ require "jam_ruby/mq_router"
 require "jam_ruby/connection_manager"
 require "jam_ruby/version"
 require "jam_ruby/message_factory"
+require "jam_ruby/models/genre"
 require "jam_ruby/models/user"
 require "jam_ruby/models/musician"
 require "jam_ruby/models/band"
diff --git a/lib/jam_ruby/models/band.rb b/lib/jam_ruby/models/band.rb
index 4a26f47b2..fda27e818 100644
--- a/lib/jam_ruby/models/band.rb
+++ b/lib/jam_ruby/models/band.rb
@@ -3,7 +3,7 @@ module JamRuby
 
   	self.primary_key = 'id'
 
-    has_and_belongs_to_many :musicians
+    has_and_belongs_to_many :musicians, :class_name => "JamRuby::Musician"
 
   end
 end
\ No newline at end of file
diff --git a/lib/jam_ruby/models/friendship.rb b/lib/jam_ruby/models/friendship.rb
index d3ab45e27..924e01c76 100644
--- a/lib/jam_ruby/models/friendship.rb
+++ b/lib/jam_ruby/models/friendship.rb
@@ -3,7 +3,7 @@ module JamRuby
 
     self.primary_key = 'id'
 
-    belongs_to :user
+    belongs_to :user, :class_name => "JamRuby::User"
     belongs_to :friend, :class_name => "JamRuby::User"
 
   end
diff --git a/lib/jam_ruby/models/genre.rb b/lib/jam_ruby/models/genre.rb
new file mode 100644
index 000000000..c70b0e251
--- /dev/null
+++ b/lib/jam_ruby/models/genre.rb
@@ -0,0 +1,10 @@
+module JamRuby
+  class Genre < ActiveRecord::Base
+
+  	self.primary_key = 'id'
+
+    has_and_belongs_to_many :musicians, :class_name => "JamRuby::Musician"
+    has_and_belongs_to_many :music_sessions, :class_name => "JamRuby::MusicSession", :join_table => "genres_music_sessions"
+
+  end
+end
\ No newline at end of file
diff --git a/lib/jam_ruby/models/music_session.rb b/lib/jam_ruby/models/music_session.rb
index bf2e35054..07bcf28f4 100644
--- a/lib/jam_ruby/models/music_session.rb
+++ b/lib/jam_ruby/models/music_session.rb
@@ -6,16 +6,32 @@ module JamRuby
 
     has_many :connections, :class_name => "JamRuby::Connection"
     has_many :users, :through => :connections, :class_name => "JamRuby::User"
-         
+    has_and_belongs_to_many :genres, :class_name => "::JamRuby::Genre", :join_table => "genres_music_sessions"
+
+    after_save :require_at_least_one_genre, :limit_to_three_genres
+
     # Verifies that the specified user can join this jam session
     def access?(user)
-        #return self.public || self.users.exists?(user)
-        return true
+      #return self.public || self.users.exists?(user)
+      return true
     end
 
     def to_s
-        return description
+      return description
     end
 
+    private
+
+    def require_at_least_one_genre
+      if genres.count == 0
+        errors.add(:genres, "Please select at least one genre")
+      end
+    end
+
+    def limit_to_three_genres
+      if genres.count > 3
+        errors.add(:genres, "Three genres at most, please")
+      end
+    end
   end
 end
diff --git a/lib/jam_ruby/models/musician.rb b/lib/jam_ruby/models/musician.rb
index 1cc55a29d..bf3dbdbb5 100644
--- a/lib/jam_ruby/models/musician.rb
+++ b/lib/jam_ruby/models/musician.rb
@@ -3,7 +3,7 @@ module JamRuby
 
     self.primary_key = 'id'
 
-    has_and_belongs_to_many :bands
+    has_and_belongs_to_many :bands, :class_name => "JamRuby::Band"
 
   end
 end
\ No newline at end of file
diff --git a/lib/jam_ruby/models/user.rb b/lib/jam_ruby/models/user.rb
index d0fb588b6..38b796d3c 100644
--- a/lib/jam_ruby/models/user.rb
+++ b/lib/jam_ruby/models/user.rb
@@ -13,10 +13,10 @@ module JamRuby
 
     has_many :friend_requests, :class_name => "JamRuby::FriendRequest"
 
-    has_many :friendships
-    has_many :friends, :through => :friendships
+    has_many :friendships, :class_name => "JamRuby::Friendship"
+    has_many :friends, :through => :friendships, :class_name => "JamRuby::Friend"
     has_many :inverse_friendships, :class_name => "JamRuby::Friendship", :foreign_key => "friend_id"
-    has_many :inverse_friends, :through => :inverse_friendships, :source => :user
+    has_many :inverse_friends, :through => :inverse_friendships, :source => :user, :class_name => "JamRuby::Friend"
     
     has_many :music_session_clients, :class_name => "JamRuby::MusicSessionClient"
     has_many :created_music_sessions, :foreign_key => "user_id", :inverse_of => :user, :class_name => "JamRuby::MusicSession" # sessions *created* by the user