Big repository reorganization

The code is divided in three crates:
- plume-common, for the ActivityPub module, and some common utils
- plume-models, for the models and database-related code
- plume, the app itself

This new organization will allow to test it more easily, but also to create other tools that only reuse a little part of
the code (for instance a Wordpress import tool, that would just use the plume-models crate)

plume-models/src/instance.rs

@@ -0,0 +1,71 @@
+use chrono::NaiveDateTime;
+use diesel::{self, QueryDsl, RunQueryDsl, ExpressionMethods, PgConnection};
+use std::iter::Iterator;
+
+use plume_common::activity_pub::ap_url;
+use users::User;
+use schema::{instances, users};
+
+#[derive(Identifiable, Queryable, Serialize)]
+pub struct Instance {
+    pub id: i32,
+    pub public_domain: String,
+    pub name: String,
+    pub local: bool,
+    pub blocked: bool,
+    pub creation_date: NaiveDateTime    
+}
+
+#[derive(Insertable)]
+#[table_name = "instances"]
+pub struct NewInstance {
+    pub public_domain: String,
+    pub name: String,
+    pub local: bool
+}
+
+impl Instance {
+    pub fn get_local(conn: &PgConnection) -> Option<Instance> {
+        instances::table.filter(instances::local.eq(true))
+            .limit(1)
+            .load::<Instance>(conn)
+            .expect("Error loading local instance infos")
+            .into_iter().nth(0)
+    }
+
+    pub fn get_remotes(conn: &PgConnection) -> Vec<Instance> {
+        instances::table.filter(instances::local.eq(false))
+            .load::<Instance>(conn)
+            .expect("Error loading remote instances infos")
+    }
+
+    pub fn local_id(conn: &PgConnection) -> i32 {
+        Instance::get_local(conn).unwrap().id
+    }
+
+    insert!(instances, NewInstance);
+    get!(instances);
+    find_by!(instances, find_by_domain, public_domain as String);
+
+    pub fn block(&self) {
+        unimplemented!()
+    }
+
+    pub fn has_admin(&self, conn: &PgConnection) -> bool {
+        users::table.filter(users::instance_id.eq(self.id))
+            .filter(users::is_admin.eq(true))
+            .load::<User>(conn)
+            .expect("Couldn't load admins")
+            .len() > 0
+    }
+
+    pub fn compute_box(&self, prefix: &'static str, name: String, box_name: &'static str) -> String {
+        ap_url(format!(
+            "{instance}/{prefix}/{name}/{box_name}",
+            instance = self.public_domain,
+            prefix = prefix,
+            name = name,
+            box_name = box_name
+        ))
+    }
+}