added missing proxyexercise which caused problems when recommending exercises

db/migrate/20170321150454_add_reason_to_user_proxy_exercise_exercise.rb

@@ -0,0 +1,7 @@
+class AddReasonToUserProxyExerciseExercise < ActiveRecord::Migration
+  def change
+    change_table :user_proxy_exercise_exercises do |t|
+      t.string :reason
+    end
+  end
+end