#166075487 Connect loan model to postgres database

[chidimo]

What does this PR do?

Connect loan model to postgres database

Description of Task to be completed?

1. Make use of methods defined in /models/Model.js to send SQL queries using pg.
2. Use async/await to gather the results of such queries and return it.
3. Create helper functions in /controllers/helpers/LoansController to handle repetitive tasks.
4. Use psql with node's exec to populate and clear out the test database tables

How should this be manually tested?

1. Clone the repo
2. cd into the root folder on a cmd shell and run yarn install. PowerShell is fine also.
3. Setup a PostgreSQL DB.
4. Define a .env file in the root of the project and supply values for the following parameters

   JWT_SECRET=<json-web-token-secret>
   PGPASSWORD=<postgres-db-password>
   PGHOST=<postgres-db-host>
   PGUSER=<postgres-db-user>
   PGPORT=<postgres-db-port>

5. Create a PostgreSQL database called testdb.
6. Create the database tables listed below.
7. Now run the tests with yarn test

CREATE TABLE users (
	id SERIAL PRIMARY KEY,
	email VARCHAR NOT NULL UNIQUE,
    password VARCHAR NOT NULL,
    firstname VARCHAR DEFAULT '',
    lastname VARCHAR DEFAULT '',
    phone VARCHAR DEFAULT '',
    address jsonb DEFAULT '{"home": "", "office": ""}',
    status VARCHAR DEFAULT 'unverified',
    isAdmin BOOLEAN DEFAULT false
);

CREATE TABLE IF NOT EXISTS loans (
	id SERIAL PRIMARY KEY,
	userid INT NOT NULL,
    createdon TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP,
    status VARCHAR DEFAULT 'pending',
    repaid BOOLEAN DEFAULT false,
    amount FLOAT NOT NULL,
    tenor INT NOT NULL,
    interest FLOAT NOT NULL,
    balance FLOAT NOT NULL,
    paymentinstallment FLOAT NOT NULL
);

CREATE TABLE IF NOT EXISTS repayments (
    id SERIAL PRIMARY KEY,
    loanid INT NOT NULL,
    adminid INT NOT NULL,
    createdon TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP,
    amount FLOAT NOT NULL
)

1. Now run command yarn test

Any background context you want to provide?

Be sure to setup the database as instructed above

What are the relevant pivotal tracker stories?

166075487

Screenshots (if appropriate)

Nil

Questions:

Nil