Add /user/{userId} (#24)

Closes #9

Reviewed-on: #24

backend/db.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"gitea.seeseepuff.be/seeseemelk/mysqlite"
 	"log"
 )
@@ -42,3 +43,17 @@ func (db *Db) GetUsers() ([]User, error) {
 	}
 	return users, nil
 }
+
+func (db *Db) GetUser(id int) (*User, error) {
+	user := &User{}
+
+	err := db.db.Query("select id, name from users where id = ?").
+		Bind(id).ScanSingle(&user.ID, &user.Name)
+	if errors.Is(err, mysqlite.ErrNoRows) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return user, nil
+}