Add a follow model

migrations/2018-05-01-124607_create_follow/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE follows;

migrations/2018-05-01-124607_create_follow/up.sql

@@ -0,0 +1,6 @@
+-- Your SQL goes here
+CREATE TABLE follows (
+    id SERIAL PRIMARY KEY,
+    follower_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    following_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL
+)

src/models/follows.rs

@@ -0,0 +1,34 @@
+use diesel::{self, PgConnection, ExpressionMethods, QueryDsl, RunQueryDsl};
+
+use schema::follows;
+
+#[derive(Queryable, Identifiable)]
+pub struct Follow {
+    pub id: i32,
+    pub follower_id: i32,
+    pub following_id: i32
+}
+
+#[derive(Insertable)]
+#[table_name = "follows"]
+pub struct NewFollow {
+    pub follower_id: i32,
+    pub following_id: i32
+}
+
+impl Follow {
+    pub fn insert(conn: &PgConnection, new: NewFollow) -> Follow {
+        diesel::insert_into(follows::table)
+            .values(new)
+            .get_result(conn)
+            .expect("Unable to insert new follow")
+    }
+
+    pub fn get(conn: &PgConnection, id: i32) -> Option<Follow> {
+        follows::table.filter(follows::id.eq(id))
+            .limit(1)
+            .load::<Follow>(conn)
+            .expect("Unable to load follow by id")
+            .into_iter().nth(0)
+    }
+}

src/models/mod.rs

@@ -1,5 +1,6 @@
 pub mod blog_authors;
 pub mod blogs;
+pub mod follows;
 pub mod instance;
 pub mod post_authors;
 pub mod posts;

src/schema.rs

@@ -20,6 +20,14 @@ table! {
     }
 }
 
+table! {
+    follows (id) {
+        id -> Int4,
+        follower_id -> Int4,
+        following_id -> Int4,
+    }
+}
+
 table! {
     instances (id) {
         id -> Int4,
@@ -80,6 +88,7 @@ joinable!(users -> instances (instance_id));
 allow_tables_to_appear_in_same_query!(
     blog_authors,
     blogs,
+    follows,
     instances,
     post_authors,
     posts,