Submit values with link_to in Rails 5.1 - ruby-on-rails

Question

So currently i have a link_to, where signed in users can click on:
<%= link_to "Enroll", [#task.project, #task] %>
The user has an association with the project, through subscription. To create a new subscription for a user with a project, i wrote some simple form for it.
<%= form_for([#project, #subzz]) do |f| %>
<%= f.hidden_field :project_id, :value => #project.id %>
<%= f.hidden_field :user_id, :value => current_user.id %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
Which works fine and creates the association. However, i want that the user is able to create the subscription whenever he clicks on 'enroll' instead of a second, extra submit button.
Any ideas how to approach this? I thought about using jQuery, but not sure how to inject the ids with it and if its the 'right' way to do it.
Thanks in advance everyone!
EDIT:
When using the method posted as answer, i get:
param is missing or the value is empty: sub
My updatet form:
<%= form_for([#project, #subzz], html: {role: "form", id: "project_form"}) do |f| %>
<%= hidden_field_tag :project_id, :value => #project.id %>
<%= hidden_field_tag :user_id, :value => current_user.id %>
<%= link_to "Enroll", [#task.project, #task], :onclick => "$('#project_form').submit() "%>
<% end %>
subs_controller.rb
class SubsController < ApplicationController
def create
#subz = Sub.create(sub_params)
project = #subz.project
redirect_to root_path
end
private
def sub_params
params.require(:sub).permit(:project_id, :user_id)
end
end

Answer 1

You can be using the existing form and link_to, just edit some like edit the dorm_tag like this
<%= form_for([#project, #subzz], html: {role: "form", id: "project_form"}) do |f| %>
and remove the button into form like this one
<div class="actions">
<%= f.submit %>
</div>
and edit the link_to like this
<%= link_to 'Enroll', "", :onclick => "$('#project_form').submit()" %>
it will work
Update
You can achieve this without a form, comment out this form and edit the link like below
<%= link_to 'Enroll', subs_path(project_id: #project.id, user_id: current_user.id), method: :post %>
and the create method update like below
def create
#subz = Sub.new(sub_params)
if #subz.save
flash[:success] = 'Sub was successfully submited.'
redirect_to root_path
else
flash[:danger] = 'Sub not submited'
redirect_to request.referer
end
end
that is easier
Or if you keep before one with form then the link out from the form and the create method edit like the following
def create
#subz = Sub.new(sub_params)
if #subz.save
flash[:success] = 'Sub was successfully submited.'
redirect_to root_path
else
flash[:danger] = 'Sub not submited'
redirect_to request.referer
end
end
and the form will look like this
<%= form_for([#project, #subzz], html: {role: "form", id: "project_form"}) do |f| %>
<%= hidden_field_tag :project_id, :value => #project.id %>
<%= hidden_field_tag :user_id, :value => current_user.id %>
<% end %>
<%= link_to "Enroll", [#task.project, #task], :onclick => "$('#project_form').submit() "%>
if you confused this [#task.project, #task] on link tag then use direct link

Answer 2

So i came up with the following solution:
I've added the sub handling to the application_controller, so that its availiable for the project_controller. I also added the project, tasks as a reference, so that i am able to redirect to a task via the sub_controller, instead of the project_controller.
application_controller.rb
def create
#subs = Sub.new(sub_params)
project = #subs.project
taskz = project.tasks.first
if #subs.save
redirect_to [taskz.project, taskz]
end
end
private
def sub_params
params.require(:sub).permit(:project_id, :user_id)
end
Inside the show.html.erb from the project_controller, i use the old form:
<%= form_for([#project, #subz] do |f| %>
<%= f.hidden_field :project_id, :value => #project.id %>
<%= f.hidden_field :user_id, :value => current_user.id %>
<%= f.submit "Submitted" %>
<% end %>
which works fine. Thanks for any previous help!