diff --git a/api/src/index.js b/api/src/index.js
index 11eba8e..5a21905 100644
--- a/api/src/index.js
+++ b/api/src/index.js
@@ -38,6 +38,7 @@ if (!isProduction) {
 }
 
 require('./db');
+require('./models');
 
 app.use(require('./routes'));
 
diff --git a/api/src/models/AccessToken.js b/api/src/models/AccessToken.js
index d8e7899..d471c58 100644
--- a/api/src/models/AccessToken.js
+++ b/api/src/models/AccessToken.js
@@ -15,7 +15,7 @@ const schema = new mongoose.Schema(
 
 schema.plugin(uniqueValidator, { message: 'reused token' });
 
-class AccessToken extends mongoose.Model {
+class AccessTokenClass extends mongoose.Model {
   toJSON() {
     return {
       token: this.token,
@@ -24,7 +24,7 @@ class AccessToken extends mongoose.Model {
   }
 
   isValid() {
-    return this.expiresAt < new Date()
+    return this.expiresAt < new Date();
   }
 
   toHeaderString() {
@@ -42,6 +42,8 @@ class AccessToken extends mongoose.Model {
   }
 }
 
-mongoose.model(AccessToken, schema);
+schema.loadClass(AccessTokenClass);
+
+const AccessToken = mongoose.model('AccessToken', schema);
 
 module.exports = AccessToken;
diff --git a/api/src/models/AuthorizationCode.js b/api/src/models/AuthorizationCode.js
index ea91043..41859a2 100644
--- a/api/src/models/AuthorizationCode.js
+++ b/api/src/models/AuthorizationCode.js
@@ -14,7 +14,7 @@ const schema = new mongoose.Schema(
   { timestamps: true },
 );
 
-class AuthorizationCode extends mongoose.Model {
+class AuthorizationCodeClass extends mongoose.Model {
   static generate(options, expiresInSeconds = 60) {
     const code = crypto.randomBytes(8).toString('hex');
 
@@ -26,6 +26,7 @@ class AuthorizationCode extends mongoose.Model {
   }
 }
 
-mongoose.model(AuthorizationCode, schema);
+schema.loadClass(AuthorizationCodeClass)
 
-module.exports = AuthorizationCode;
+const AuthorizationCode = mongoose.model('AuthorizationCode', schema);
+module.exports = AuthorizationCode
diff --git a/api/src/models/Comment.js b/api/src/models/Comment.js
index 9273542..8a40212 100644
--- a/api/src/models/Comment.js
+++ b/api/src/models/Comment.js
@@ -9,7 +9,7 @@ const schema = new mongoose.Schema(
   { timestamps: true },
 );
 
-class Comment extends mongoose.Model {
+class CommentClass extends mongoose.Model {
   toJSONFor(user) {
     return {
       id: this._id,
@@ -20,6 +20,5 @@ class Comment extends mongoose.Model {
   }
 }
 
-mongoose.model(Comment, schema);
-
-module.exports = Comment;
+schema.loadClass(CommentClass)
+module.exports = mongoose.model('Comment', schema);
diff --git a/api/src/models/RefreshToken.js b/api/src/models/RefreshToken.js
index 7847c9b..8eaf247 100644
--- a/api/src/models/RefreshToken.js
+++ b/api/src/models/RefreshToken.js
@@ -17,7 +17,7 @@ const schema = new mongoose.Schema(
 
 schema.plugin(uniqueValidator, { message: 'reused token' });
 
-class RefreshToken extends mongoose.Model {
+class RefreshTokenClass extends mongoose.Model {
   toJSON() {
     return {
       token: this.token,
@@ -40,6 +40,7 @@ class RefreshToken extends mongoose.Model {
   }
 }
 
-mongoose.model(RefreshToken, schema);
+schema.loadClass(RefreshTokenClass);
 
-module.exports = RefreshToken;
+const RefreshToken = mongoose.model('RefreshToken', schema);
+module.exports = RefreshToken
diff --git a/api/src/models/Track.js b/api/src/models/Track.js
index 33513c9..ef700f8 100644
--- a/api/src/models/Track.js
+++ b/api/src/models/Track.js
@@ -142,7 +142,7 @@ function getDaytime(dateTime) {
   return DAYTIMES[Math.floor((dateTime.hour % 24) / 2)];
 }
 
-class Track extends mongoose.Model {
+class TrackClass extends mongoose.Model {
   slugify() {
     this.slug = slug(this.title || 'track') + '-' + ((Math.random() * Math.pow(36, 6)) | 0).toString(36);
   }
@@ -301,6 +301,6 @@ class Track extends mongoose.Model {
   }
 }
 
-mongoose.model(Track, schema);
-
+schema.loadClass(TrackClass);
+const Track = mongoose.model('Track', schema);
 module.exports = Track;
diff --git a/api/src/models/User.js b/api/src/models/User.js
index 41d22f0..f49c483 100644
--- a/api/src/models/User.js
+++ b/api/src/models/User.js
@@ -39,7 +39,7 @@ const schema = new mongoose.Schema(
 
 schema.plugin(uniqueValidator, { message: 'ist bereits vergeben. Sorry!' });
 
-class User extends mongoose.Model {
+class UserClass extends mongoose.Model {
   validPassword(password) {
     const hash = crypto.pbkdf2Sync(password, this.salt, 10000, 512, 'sha512').toString('hex');
     return this.hash === hash;
@@ -86,6 +86,6 @@ class User extends mongoose.Model {
   }
 }
 
-mongoose.model(User, schema);
-
-module.exports = User;
+schema.loadClass(UserClass);
+const User = mongoose.model('User', schema);
+module.exports = User