Paperclip::Errors::MissingRequiredValidatorError with Rails 4

I’m getting this error when I try to upload using paperclip with my rails blogging app.
Not sure what it is referring to when it says “MissingRequiredValidatorError”
I thought that by updating post_params and giving it :image it would be fine, as both create and update use post_params

Paperclip::Errors::MissingRequiredValidatorError in PostsController#create
Paperclip::Errors::MissingRequiredValidatorError

Extracted source (around line #30):

def create
  @post = Post.new(post_params)

This is my posts_controller.rb

def update
  @post = Post.find(params[:id])

  if @post.update(post_params)
    redirect_to action: :show, id: @post.id
  else
    render 'edit'
  end
end

def new
  @post = Post.new
end

def create
  @post = Post.new(post_params)

  if @post.save
    redirect_to action: :show, id: @post.id
  else
    render 'new'
  end
end
#...

private

def post_params
  params.require(:post).permit(:title, :text, :image)
end    

and this is my posts helper

module PostsHelper
  def post_params
    params.require(:post).permit(:title, :body, :tag_list, :image)
  end
end

Please let me know if I can supplement extra material to help you help me.