add invites actions in controller and views

Index is added so organizer can see who they have invited. Oganizers will now be able to invite users with their email.Organizer will be able to delete and edit a invite.Add test for actions.

app/controllers/admin/invites_controller.rb

@@ -2,10 +2,69 @@ module Admin
   class InvitesController < Admin::BaseController
     load_and_authorize_resource :conference, find_by: :short_title
 
+    def index
+      @invites = Invite.where(conference_id: @conference.id)
+      @invites.each do |invite|
+        invite.emails = User.find(invite.user_id).email
+      end
+    end
+
     def new
       @invite = @conference.invites.new
     end
 
-    def create; end
+    def create
+      emails_array = invite_params[:emails].split(',')
+      invite_count = 0
+      flag = 0
+      emails_array.each do |email|
+        @invite = @conference.invites.new(invite_params)
+        new_user = User.find_by(email: email)
+        new_user = User.invite!({ email: email }, current_user) if new_user.nil?
+        @invite.user_id = new_user.id
+        invite_count += 1
+        unless @invite.save
+          flash.now[:error] = "#{(invite_count - 1)} invitations created. Creating invitation failed. #{@invite.errors.full_messages.to_sentence}."
+          flag = 1
+          break
+        end
+      end
+      if flag.zero?
+        redirect_to admin_conference_invites_path, notice: "#{invite_count.to_s + ' invitation'.pluralize(invite_count)} successfully created."
+      else
+        render 'new'
+      end
+    end
+
+    def edit
+      @invite = Invite.find(params[:id])
+    end
+
+    def update
+      @invite = Invite.find(params[:id])
+      if @invite.update_attributes(invite_params)
+        redirect_to admin_conference_invites_path,
+                    notice: 'Invitation successfully updated.'
+      else
+        flash.now[:error] = "Creating invitation failed. #{@invite.errors.full_messages.to_sentence}."
+        render 'edit'
+      end
+    end
+
+    def destroy
+      if Invite.find(params[:id]).destroy
+        redirect_to admin_conference_invites_path,
+                    notice: 'Invitation deleted.'
+      else
+        redirect_to admin_conference_invites_path,
+                    notice: 'Unable to delete the invitation.'
+      end
+    end
+
+    private
+
+    def invite_params
+      params.require(:invite).permit(:emails, :end_date, :invite_for)
+    end
   end
 end