Enable staging deployment

[Naramsim]

This PR allows invoking in a conditional manner a new deploy job present in the PokeAPI/deploy CircleCI configuration. This job will automatically deploy the api-data data to our productive environment (pokeapi.co) or to a new staging environment. The job will be invoked only when the master or staging branches of this repository are pushed to. If the master is getting pushed then the master branch will be deployed in the productive environment. Viceversa, if the staging branch is pushed, then the staging branch will be deployed in the staging environment.

A more descriptive and general overview is detailed in this PokeAPI/pokeapi#488 PR.

---

This PR is linked to the following PRs:

• Enable staging deployment deploy#10
• Enable staging deployment pokeapi.co#76
• Update data automatically and enable staging deployment pokeapi#488

When PokeAPI/deploy#10 will be merged we need to change .circleci/config.yml#38, updater/cmd.bash#33, updater/cmd.bash#36

This PR should be merged after PokeAPI/deploy#10

[phalt]

Nice work man, real good.

[sargunv]

approved assuming the present TODOs are taken care of before merging

[sargunv]

Assuming Bash 4 is available on the host, I'd organize this with something like this (untested):

also rename the file to .bash instead of .sh if you do this to make it obvious it uses bash syntax

#!/usr/bin/env bash

declare -A BRANCH_TO_URL=(
    ["master"]="https://pokeapi.co"
    ["staging"]="https://pokeapi-test-b6137.firebaseapp.com"
)

BASE_URL="${BRANCH_TO_URL[$CIRCLE_BRANCH]}"
~/.local/bin/ditto transform --base-url="$BASE_URL" --src-dir=data --dest-dir=_gen