Rails - Seeding the database with nil instead of values - ruby-on-rails

Question

I have created an app in Rails 4.2.3
I am trying to seed the database but after I do rake db:migrate I am getting nil values in the field of the database table. The only piece of code I have in my seeds.rb is:
User.create![{username: "test", password_digest: "test"}]
In my schema.rb I have:
create_table "users", force: :cascade do |t|
t.string "username"
t.string "password_digest"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
My User model is:
class User < ActiveRecord::Base
has_one :profile, dependent: :destroy
has_many :todo_lists, dependent: :destroy
has_many :todo_items, through: :todo_lists, source: :todo_items
end
There are other people that experienced the same problem like here and here but I don't think that the solutions apply to my case as I do not have any attr_accessor in any of my models.
Anyone knows why that might be happening?

Answer 1

brace-types matter...
use the following instead
User.create!( username: "test", password_digest: "test" )
This tells rails to create a single user, using the hash that contains username "test" and password "test"
what you have is telling rails to create a user with an array [] that contains a hash {}... but create is not expecting an array of hashes - it's expecting just a single hash.
EDIT: re: using []
That's because when you don't use () but do use [], then ruby has to guess what you mean...
are you passing an array to a method or are you calling the array-indexing method on a variable? (or hash-indexing if it's not an integer in the brackets)?
If you put the [] right next to the word create! (eg User.create![]) ruby will probably interpret that as the latter... eg it's looking for an variable on the User class called create!... and then tries to look for a key of that hash called {username: "test", password_digest: "test"}, {username: "test2", password_digest: "test2"} and then it gets confused because when you use the array-indexing method [] you should pass it only one key to find, not two ({username: "test", password_digest: "test"} is the first and {username: "test2", password_digest: "test2"} is the second)... thus giving you the error that you're trying ot pass 2 arguments instead of one... but also just using the wrong interpretation to begin with.
neither of which is what you want...
If you leave a space between the [] and create! then ruby is more likely to interpret the [] as a parameter being passed to a method... and then it triggers a different error.
To be unambiguous - always use a space... or use parens () when passing an argument that could be ambiguous in this way.