diff --git a/src/db.rs b/src/db.rs
index 9003553..4c6537e 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -9,11 +9,11 @@ pub struct OAuthApplication {
 
 impl OAuthApplication {
     // TEST: functionality
-    pub fn new() -> Self {
+    pub fn create() -> Self {
         Self { client_id: Uuid::new_v4(), client_secret: crate::misc::random_256() }
     }
 
-    pub fn from(client_id: Uuid, client_secret: crate::misc::U256) -> Self {
+    pub fn new(client_id: Uuid, client_secret: crate::misc::U256) -> Self {
         Self { client_id, client_secret }
     }
 }
@@ -30,6 +30,26 @@ impl OAuthHashedApplication {
     pub fn from(app: &OAuthApplication) -> Self {
         Self { client_id: app.client_id, client_secret: crate::misc::digest(&app.client_secret) }
     }
+
+    pub fn new(client_id: &Uuid, client_secret: &Vec<u8>) -> Self {
+        Self { client_id: client_id.to_owned(), client_secret: client_secret.to_owned() }
+    }
+}
+
+pub struct OAuthApplicationAccess {
+    pub access_id: Uuid,
+    pub client_id: Uuid,
+    pub scope_id: Uuid,
+}
+
+impl OAuthApplicationAccess {
+    pub fn create(app: &OAuthHashedApplication, scope: &OAuthScope) -> Self {
+        Self { access_id: Uuid::new_v4(), client_id: app.client_id, scope_id: scope.scope_id }
+    }
+
+    pub fn new(access_id: &Uuid, client_id: &Uuid, scope_id: &Uuid) -> Self {
+        Self { access_id: access_id.to_owned(), client_id: client_id.to_owned(), scope_id: scope_id.to_owned() }
+    }
 }
 
 pub struct OAuthScope {
@@ -39,11 +59,11 @@ pub struct OAuthScope {
 
 impl OAuthScope {
     // TEST: functionality
-    pub fn new(description: String) -> Self {
+    pub fn create(description: String) -> Self {
         Self { scope_id: Uuid::new_v4(), scope_desc: description }
     }
 
-    pub fn from(scope_id: Uuid, scope_desc: String) -> Self {
+    pub fn new(scope_id: Uuid, scope_desc: String) -> Self {
         Self { scope_id, scope_desc }
     }
 }
@@ -54,6 +74,19 @@ pub struct OAuthDatabase {
     handle: tokio::task::JoinHandle<Result<(), tokio_postgres::Error>>,
 }
 
+pub struct OAuthUser {
+    pub user_id: Uuid,
+}
+
+impl OAuthUser {
+    pub fn create() -> Self {
+        Self { user_id: Uuid::new_v4() }
+    }
+    pub fn new(user_id: Uuid) -> Self {
+        Self { user_id }
+    }
+}
+
 impl OAuthDatabase {
     /// Establish a new connection to a database.
     pub async fn connect(host: &str, port: u16, user: &str, password: &str, db_name: &str) -> Result<Self, tokio_postgres::Error> {
@@ -91,8 +124,8 @@ impl OAuthDatabase {
         // TEST: functionality
         self.psql_execute("create table Applications(client_id uuid primary key, client_secret bytea)", &[]).await?;
         self.psql_execute("create table Scopes(scope_id uuid primary key, scope_desc text)", &[]).await?;
-        // TODO: OAuthApplicationAccess struct
         self.psql_execute("create table ApplicationAccess(access_id uuid primary key, client_id uuid, scope_id uuid)", &[]).await?;
+        self.psql_execute("create table Users(user_id uuid primary key)", &[]).await?;
         Ok(())
     }
 
@@ -100,7 +133,7 @@ impl OAuthDatabase {
     /// Applicant: client
     pub async fn trusted_register_application(&mut self) -> Result<OAuthApplication, tokio_postgres::Error> {
         // TEST: functionality
-        let app = OAuthApplication::new();
+        let app = OAuthApplication::create();
         let app_hash = OAuthHashedApplication::from(&app);
         self.psql_execute("insert into Applications (client_id, client_secret) values ($1, $2)", &[&app_hash.client_id, &app_hash.client_secret]).await?;
         Ok(app)
@@ -110,17 +143,26 @@ impl OAuthDatabase {
     /// Applicant: resource
     pub async fn trusted_register_scope(&mut self, description: String) -> Result<OAuthScope, tokio_postgres::Error> {
         // TEST: functionality
-        let scope = OAuthScope::new(description);
+        let scope = OAuthScope::create(description);
         self.psql_execute("insert into Scopes (scope_id, scope_desc) values ($1, $2)", &[&scope.scope_id, &scope.scope_desc]).await?;
         Ok(scope)
     }
 
     /// Register an access relation.
     /// Applicant: client
-    pub async fn trusted_register_access(&mut self, app: OAuthHashedApplication, scope: OAuthScope) -> Result<(), tokio_postgres::Error> {
-        // TODO: implementation
+    pub async fn trusted_register_access(&mut self, app: &OAuthHashedApplication, scope: &OAuthScope) -> Result<(), tokio_postgres::Error> {
+        let access = OAuthApplicationAccess::create(app, scope);
+        self.psql_execute("insert into ApplicationAccess(access_id, client_id, scope_id) values($1, $2, $3)", &[&access.access_id, &access.client_id, &access.scope_id]).await?;
         Ok(())
     }
+
+    /// Register a user.
+    /// Applicant: resource
+    pub async fn trusted_register_user(&mut self) -> Result<OAuthUser, tokio_postgres::Error> {
+        let user = OAuthUser::create();
+        self.psql_execute("insert into Users(user_id) values ($1)", &[&user.user_id]).await?;
+        Ok(user)
+    }
 }
 
 #[cfg(test)]
diff --git a/src/main.rs b/src/main.rs
index 8d5d7b3..c775724 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,25 +4,12 @@ use tide::prelude::*;
 mod db;
 mod misc;
 
-#[derive(Serialize, Deserialize)]
-struct Test {
-    x: i32,
-    y: i32
-}
-
-impl Test {
-    fn new(x: i32, y: i32) -> Self {
-        Self { x, y }
-    }
-}
-
 #[tokio::main]
 async fn main() {
-    let a = Test::new(2, 3);
     let mut b = db::OAuthDatabase::connect("localhost", 5432, "postgres", "configjson", "myoauth").await.unwrap();
-    // let s = serde_json::to_string(&a);
-    // json!(a);
-    println!("{}", json!(a));
+    // b.init().await.unwrap();
+    let u = b.trusted_register_user().await.unwrap();
+    println!("Successfully registered user with uid = {}", u.user_id);
 }
 
 #[tokio::test]