title: ActiveModel::MissingAttributeError (can't write unknown attribute `user_id`)
body: <p>I have problems with my comments when my app is deployed. Locally everything is working. The logs from heroku says:</p>
  
  <pre><code>ActiveModel::MissingAttributeError (can't write unknown attribute `user_id`):
  2018-01-02T15:52:43.461794+00:00 app[web.1]: [79cd7190-e2d9-4dd0-bf71-
  709552e5c6e5] app/controllers/comments_controller.rb:15:in `create'
  </code></pre>
  
  <p>I have no ideas what is occuring the error. Maybe some database thing?</p>
  
  <p><strong>My CommentsController</strong></p>
  
  <pre><code>class CommentsController &lt; ApplicationController
  
  def create 
      @post =Post.find(params[:post_id])
      @comment =@post.comments.create(params[:comment].permit(:name, :body).merge(user: current_user))
      redirect_to post_path(@post)
  end
  
  
  def destroy 
  
      @post = Post.find(params[:post_id])
      @comment= @post.comments.find(params[:id])
      if current_user.id == @comment.user_id 
          @comment.destroy
      end
      redirect_to post_path(@post)
  end
  end
  </code></pre>
  
  <p><strong>My Models</strong></p>
  
  <pre><code>class User &lt; ApplicationRecord
   has_many :posts
  
   devise :database_authenticatable, :registerable,
          :recoverable, :rememberable, :trackable, :validatable
  end
  
  class Post &lt; ApplicationRecord
    belongs_to :user, optional: true
    has_many :comments, dependent: :destroy
  
    validates :title, presence: true, length: {minimum: 5}
    validates :body, presence: true
  
  end
  
  class Comment &lt; ApplicationRecord
   belongs_to :post
   belongs_to :user
  end
  </code></pre>
  
  <p><strong>My migration-file</strong></p>
  
  <pre><code>class CreateComments &lt; ActiveRecord::Migration[5.1]
   def change
   create_table :comments do |t|
     t.string :name
     t.text :body
     t.references :post, index: true
  
     t.timestamps
   end
   end
  end
  </code></pre>
  
  <p>if you need more code or have any ideas please let me know </p>
  
  <p>EDIT: if i add a user_id column i get a <code>SQLite3::SQLException: duplicate column name: user_id: ALTER TABLE "comments" ADD "user_id" integer</code> error</p>
  
  <p><strong>My schema.rb</strong></p>
  
  <pre><code>`create_table "comments", force: :cascade do |t|
  t.string "name"
  t.text "body"
  t.integer "post_id"
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
  t.integer "user_id"
  t.index ["post_id"], name: "index_comments_on_post_id"
  end
  
  create_table "posts", force: :cascade do |t|
  t.string "title"
  t.text "body"
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
  t.string "image_file_name"
  t.string "image_content_type"
  t.integer "image_file_size"
  t.datetime "image_updated_at"
  t.string "theme"
  t.integer "user_id"
  end
  
  create_table "users", force: :cascade do |t|
  t.string "email", default: "", null: false
  t.string "encrypted_password", default: "", null: false
  t.string "reset_password_token"
  t.datetime "reset_password_sent_at"
  t.datetime "remember_created_at"
  t.integer "sign_in_count", default: 0, null: false
  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.index ["email"], name: "index_users_on_email", unique: true
  t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
  end
  </code></pre>