How to setup belongsToMany Relation with additionnal attribute in the join table in featherjs with feather-sequelize

I want to add a many to many relationship between two model with feather-sequelize and in the join table, I want to add additionnal attribut. The documentation of sequelize is clear about it: I have to create a new model an use I like this

const User = sequelize.define('user', {})
const Project = sequelize.define('project', {})
const UserProjects = sequelize.define('userProjects', {
    status: DataTypes.STRING
})

User.belongsToMany(Project, { through: UserProjects })
Project.belongsToMany(User, { through: UserProjects })

But when I define a new model in my feather application, it is not created in the database so my relation is not working

Just to check if I understand correctly: you want to have a link table (eg. user_projects), and map the UserProjects model to it, thus creating a many-to-many relationship between User and Project models?

You can use the hasMany and belongsTo functions, instead of belongsToMany like:

User.hasMany(UserProjects, {
  as: 'UserProjects',
  foreignKey: 'user_id' // this is what you're missing
});
Project.hasMany(UserProjects, {
  as: 'UserProjects',
  foreignKey: 'project_id' // this is what you're missing
});

UserProjects.belongsTo(User, {
  as: 'Users',
  foreignKey: 'user_id'
});
UserProjects.belongsTo(Projects, {
  as: 'Projects',
  foreignKey: 'project_id'
});

And you need to define the user_id and project_id columns in your link table, as Foreign Keys.

Then you can add whatever other attributes you want in your link table (status or whatever else, it doesn't matter)