Add endpoints to toggle the recommendation process

[1jeanpaul1]

Problem

1. We need a way to toggle the procedure that creates the user recommendations
2. We need a way to get user recommendations

Solution

1. Add endpoint http://localhost:5000/user_recommendation/v1/toggle
   • Toggles the procedure that creates the user recommendations
2. Add endpoint: http://localhost:5000/user_recommendation/v1
   • Gets user product recommendations

Testing

1. Make an api request to http://localhost:5000/dev/v1/populate_data
   • This will populate your database with 2 Users and 3 Products. This is enough
     to test the generic version of the recommendation system (based on popularity)
2. To toggle the recommendation process make an API request to http://localhost:5000/user_recommendation/v1/toggle
3. To see a user's recommendation make an api request to http://localhost:5000/user_recommendation/v1?userId=1
   (Where userId can be the id of any user in the database)