add optional search_index to yaml files

[ilsiepotamus]

Description

• Added an optional field for yaml files- search_index- this allows you to specify which field in your mock data you want to use as an index when CRUD'ing.

Test Steps

• [x] edit schemas/systems.yaml - change search_index from "id" to "name"
• [x] install Docker Engine
• [x] in this directory, docker build -t covalent-data .
• [x] docker run -p 8080:8080 --name covalent-data covalent-data (docker stop covalent-data to stop)
• [x] GET to http://localhost:8080/systems
• [x] select one of the returned systems, grab the name, and do GET to http://localhost:8080/systems/{name}

[kyleledbetter]

nice! so i can use something like http://localhost:8080/systems/gypsum instead of http://localhost:8080/systems/5f78207d-5099-4d17-8323-9bce55370b1f right?

[ilsiepotamus]

@kyleledbetter yep!