The find(:all, :conditions => [])
was deprecated in Rails 3.2. Instead try:
def index
@posts = Post.where(:user_id => current_user)
end
Also, make sure you are adding a user_id in the create method in your controller:
def create
@post = post.new(post_params)
@post.user_id = current_user
REST OF CODE GOES HERE
end