esitoken model and relationship

app/User.php

@@ -59,4 +59,8 @@ class User extends Authenticatable
     public function esiscopes() {
         return $this->hasMany('App\Models\EsiScope');
     }
+
+    public function esitoken() {
+        return $this->hasOne('App\Models\EsiToken');
+    }
 }

database/migrations/2018_10_29_003021_create_esi_tokens.php

@@ -15,7 +15,8 @@ class CreateEsiTokens extends Migration
     {
         Schema::create('EsiTokens', function(Blueprint $table) {
             $table->integer('id')->increments();
-            $table->integer('character_id');
+            $table->integer('character_id')->unique();
+            $table->foreign('character_id')->references('character_id')->on('users');
             $table->string('access_token');
             $table->string('refresh_token');
             $table->integer('expires_in');