added database stuff

added clap arguments
added the gen_or_get_key func in lib
git ignore for .env
migrations

crates/cli/src/db/mod.rs

@@ -0,0 +1,14 @@
+use diesel::prelude::*;
+use dotenvy::dotenv;
+use std::env;
+
+pub mod models;
+pub mod schema;
+
+pub fn establish_connection() -> SqliteConnection {
+    dotenv().ok();
+
+    let database_url = env::var("DATABASE_URL").expect("DATABASE_URL must be set");
+    SqliteConnection::establish(&database_url)
+        .unwrap_or_else(|_| panic!("Error connecting to {}", database_url))
+}