feat: add diesel, but not works

__database/diesel/src/main.rs

@@ -0,0 +1,37 @@
+#[macro_use]
+extern crate diesel;
+
+pub mod schema;
+pub mod models;
+
+use diesel::prelude::*;
+use diesel::sqlite::SqliteConnection;
+use dotenv::dotenv;
+use std::env;
+use crate::models::Post;
+
+fn main() {
+    use crate::schema::posts::dsl::*;
+
+    let connection = establish_connection();
+    let results = posts.filter(published.eq(true))
+        .limit(5)
+        .load::<Post>(&connection)
+        .expect("Error loading posts");
+
+    println!("Displaying {} posts", results.len());
+    for post in results {
+        println!("{}", post.title);
+        println!("----------\n");
+        println!("{}", post.body);
+    }
+}
+
+pub fn establish_connection() -> SqliteConnection {
+    dotenv().ok();
+
+    let database_url = env::var("DATABASE_URL")
+        .expect("DATABASE_URL must be set");
+    SqliteConnection::establish(&database_url)
+        .expect(&format!("Error connecting to {}", database_url))
+}

__database/diesel/src/models.rs

@@ -0,0 +1,7 @@
+#[derive(Queryable)]
+pub struct Post {
+    pub id: i32,
+    pub title: String,
+    pub body: String,
+    pub published: bool,
+}

__database/diesel/src/schema.rs

@@ -0,0 +1,8 @@
+table! {
+    posts (id) {
+        id -> Nullable<Integer>,
+        title -> Text,
+        body -> Text,
+        published -> Bool,
+    }
+}