Added colours for teams

app/serializers/reservation_serializer.rb

@@ -0,0 +1,6 @@
+class ReservationSerializer < ActiveModel::Serializer
+  attributes :id, :start_time, :end_time
+  
+  belongs_to :customer
+  belongs_to :team, serializer: TeamSerializer
+end 

app/serializers/team_serializer.rb

@@ -0,0 +1,9 @@
+class TeamSerializer < ActiveModel::Serializer
+  include ColorHelper
+
+  attributes :id, :name, :color
+
+  def color
+    team_color(object.id)
+  end
+end