feat: init postgres implementation via sqlx

db/db-sqlx-postgres/migrations/20210310122154_mcaptcha_users.sql

@@ -0,0 +1,8 @@
+CREATE TABLE IF NOT EXISTS mcaptcha_users (
+	name VARCHAR(100) NOT NULL UNIQUE,
+	email VARCHAR(100) UNIQUE DEFAULT NULL,
+	email_verified BOOLEAN DEFAULT NULL,
+    secret varchar(50) NOT NULL UNIQUE,
+	password TEXT NOT NULL,
+	ID SERIAL PRIMARY KEY NOT NULL
+);