ruby on rails - Migration for Users Following Posts -

in application, have models users , projects.

i want users have ability follow many projects. users has_many projects, , projects belongs_to users not created them users follow them too.

so generated migration called projectrelationship , tried make flow below, doesn't seem work. can me fix associations?

thanks help!

project_relationship.rb

class projectrelationship < activerecord::base   belongs_to :user   belongs_to :project end 

project.rb

belongs_to :user has_many :project_relationships has_many :followers, through: :project_relationships, source: :user 

user.rb

has_many :projects has_many :project_relationships has_many :projects_followed, through: :project_relationships, source: :project 

schema.rb

create_table "project_relationships", :force => true |t|   t.integer  "follower_id"   t.datetime "created_at",     :null => false   t.datetime "updated_at",     :null => false   t.integer  "projectuser_id" end  add_index "project_relationships", ["follower_id"], :name => "index_project_relationships_on_follower_id", :unique => true add_index "project_relationships", ["projectuser_id"], :name => "index_project_relationships_on_projectuser_id" 

projects/show.html.erb

<%= @project.followers.count %> 

you need specify foreign keys. projectrelationship model expecting corresponding table have "user_id" , "project_id" columns. however, used different names. either specify foreign keys:

class projectrelationship < activerecord::base   belongs_to :user, foreign_key: "follower_id"   belongs_to :project, foreign_key: "projectuser_id" end 

or change column names in migration:

create_table :project_relationships |t|   t.integer :user_id   t.integer :project_id   ... end 

you need specify foreign key in other models:

class project < activerecord::base   belongs_to :user   has_many :project_relationships, foreign_key: "projectuser_id"   has_many :followers, through: :project_relationships, source: :user end  class user < activerecord::base   has_many :projects   has_many :project_relationships, foreign_key: "follower_id"   has_many :projects_followed, through: :project_relationships, source: :project end