Restore users assoc with project

app/models/project.rb

@@ -56,12 +56,14 @@ class Project < ActiveRecord::Base
   has_many :merge_requests,     dependent: :destroy
   has_many :issues,             dependent: :destroy, order: "state DESC, created_at DESC"
   has_many :milestones,         dependent: :destroy
-  has_many :users_projects,     dependent: :destroy
   has_many :notes,              dependent: :destroy
   has_many :snippets,           dependent: :destroy, class_name: "ProjectSnippet"
   has_many :hooks,              dependent: :destroy, class_name: "ProjectHook"
   has_many :protected_branches, dependent: :destroy
+  has_many :users_projects, dependent: :destroy
+  has_many :users, through: :users_projects
+
   has_many :deploy_keys_projects, dependent: :destroy
   has_many :deploy_keys, through: :deploy_keys_projects