Restructure folders (#411)

database_interactions/pg/sql/add_user.sql

@@ -0,0 +1,3 @@
+INSERT INTO testing.users(email, first_name, last_name, username)
+VALUES ($1, $2, $3, $4)
+RETURNING $table_fields;

database_interactions/pg/sql/get_users.sql

@@ -0,0 +1 @@
+SELECT $table_fields FROM testing.users;

database_interactions/pg/sql/schema.sql

@@ -0,0 +1,11 @@
+DROP SCHEMA IF EXISTS testing CASCADE;
+CREATE SCHEMA testing;
+
+CREATE TABLE testing.users (
+	id  BIGSERIAL PRIMARY KEY,
+	email       VARCHAR(200) NOT NULL,
+	first_name  VARCHAR(200) NOT NULL,
+	last_name   VARCHAR(200) NOT NULL,
+	username    VARCHAR(50) UNIQUE NOT NULL,
+	UNIQUE (username)
+);