Populate Rails Form With Model Information From Another Controller - ruby-on-rails

Question

I've renamed the SessionsController and Session Model to Periods/Period because it conflicted with Devise and so you'll see this in the update
I have a sessions and events model/controller. When a new session is created, it needs to be associated with a particular event.
In my sessions model, I have an event_id, but I want to have a dropdown on the form that is populated with name of non-past events. Once that is selected, the form should be able to assign the correct event_id to the created session.
What is the correct way to go about doing this?
Here is my schema.rb to help you get a clearer picture of what the Models look like:
ActiveRecord::Schema.define(:version => 20120807154707) do
create_table "events", :force => true do |t|
t.string "name"
t.date "date"
t.string "street"
t.string "city"
t.string "state"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "sessions", :force => true do |t|
t.string "name"
t.integer "event_id"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :default => "", :null => false
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
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.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.boolean "admin", :default => false
end
add_index "users", ["email"], :name => "index_users_on_email", :unique => true
end
Here is my form:
<%= form_for(#period) do |f| %>
<%= f.label :Name %>
<%= f.text_field :name%>
<%= f.label :Event %>
<%= f.collection_select(:period, :event_id, Event.all, :id, :name)%>
<%= f.label :time %>
<%= f.text_field :time, id: "timepicker" %>
<%= f.submit "Create Event" %>
<% end %>
and I keep getting the following error: undefined methodmerge' for :name:Symbol`
Breaking out the various arguments of collection select: f.collection_select(:period, :event_id, Event.all, :id, :name)
:period -> The object
:event_id -> the method I want to set on the object.
Event.All -> The collection (for now I'll take all of them)
:id -> the value of the html element option
:name -> the value displayed to the user
Am I doing that correct?

Answer 1

To display a select menu with options from another model (not another controller), try collection_select.
In your new Session form, this might look like:
collection_select(:event, :id, Event.where("date > :date", date: Time.now.strftime("%m/%d/%Y"))
In the Sessions controller, in the create action, build the association like this:
#session.event = Event.find(params[:event][:id])

Answer 2

I have found that this structure works for me:
<%= f.label :event %>
<%= f.collection_select :event_id, Event.all, :id, :name, {:prompt=> "Pick an Event"}, {:class => "form-control"} %>
The last bit was the html part which I used to set the Bootstrap class.
:name here could be :date or :street etc...