Create a model

[lorenamitrea]

• [x] Create a new Django app called sample_data
• [x] Create a simple table
• [x] Use makemigrations & migrate to reflect the changes in the database
• [x] Make sure that every time the project is started all the migrations are applied
• [x] Implement a management command called "populate_sample_data" that populates the database with some sample data
• [x] Implement an endpoint that returns in a json all the information in the table