Rails: add relationship with other table for Devise user - ruby-on-rails

Question

I want to add an input to my Devise user sign_up form in order to add a team name. I created a specific table for Teams and I created a relationship: Users belong to Team. Team has many users.
The problem is I need to add a Team_id when submiting the sign_up form. How can I save the value of the Team input in the register form to the Team table and get the Id in order to save it to the team_id entry in Devise User table?
My Sign Up form:
<div class="container_index">
<h2>Sign up</h2>
<%= form_for(resource, as: resource_name, url: registration_path(resource_name)) do |f| %>
<%= devise_error_messages! %>
<div class="field">
<%= f.label :email %><br />
<%= f.email_field :email, autofocus: true %>
</div>
<div class="field">
<%= f.label :password %>
<% if #minimum_password_length %>
<em>(<%= #minimum_password_length %> characters minimum)</em>
<% end %><br />
<%= f.password_field :password, autocomplete: "off" %>
</div>
<div class="field">
<%= f.label :password_confirmation %><br />
<%= f.password_field :password_confirmation %>
</div>
<div class="field">
<%= f.label :team %><br />
<%= f.text_field :team %>
</div>
<div class="actions">
<%= f.submit "Sign up" %>
</div>
<% end %>
<%= render "devise/shared/links" %>
</div>
My user schema:
create_table "users", force: :cascade do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", default: 0, null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.integer "team_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["email"], name: "index_users_on_email", unique: true
t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
t.index ["team_id"], name: "index_users_on_team_id"
end
My application controller:
class ApplicationController < ActionController::Base
protect_from_forgery with: :exception
skip_before_action :verify_authenticity_token
before_filter :configure_permitted_parameters, if: :devise_controller?
protected
def configure_permitted_parameters
devise_parameter_sanitizer.permit(:sign_up) { |u| u.permit(:name, :email, :password, :team) }
devise_parameter_sanitizer.permit(:account_update) { |u| u.permit(:name, :email, :password, :current_password, :team) }
end
Thank you.