Rails: create relationship between user posts comments and likes - ruby-on-rails

Question

I am trying to implement likes into my rails app.
like model
class Like < ApplicationRecord
belongs_to :comment
belongs_to :post
belongs_to :user
validates :user_id, uniqueness: {scope: :post_id}
validates :user_id, uniqueness: {scope: :comment_id}
end
user model
class User < ApplicationRecord
has_secure_password
has_one :profile, dependent: :destroy
has_many :comments, dependent: :destroy
has_many :posts, dependent: :destroy
has_many :likes, dependent: :destroy
has_many :liked_comments, :through => :likes, :source => :comment, dependent: :destroy
has_many :liked_posts, :through => :likes, :source => :post, dependent: :destroy
has_one_attached :avatar
validates :username, presence: true, uniqueness: true
validates :email, presence: true, uniqueness: true
validates :email, format: { with: URI::MailTo::EMAIL_REGEXP }
validates :password, length: { minimum: 8 }
validates :password, format: { with: /\A[a-zA-Z0-9!##$%^&*()_]+\z/ }
# validates :password, confirmation: true
# validates :password_confirmation, presence: true
end
post & comment model
class Post < ApplicationRecord
belongs_to :category
belongs_to :user
has_many :comments, dependent: :destroy
has_many :likes, dependent: :destroy
has_many :liking_users, :through => :likes, :source => :user
has_many_attached :images
def liked?(user)
!!self.likes.find{|like| like.user_id == user.id}
end
end
class Comment < ApplicationRecord
belongs_to :post
belongs_to :user
has_many :likes, dependent: :destroy
has_many :liking_users, :through => :likes, :source => :user
has_many_attached :images
def liked?(user)
!!self.likes.find{|like| like.user_id == user.id}
end
end
The issue I'm having is when I run my seed data I get one of two errors NoMethodError: undefined method "marked_for_destruction?" for false:FalseClass if set up like so:
#like0 = Like.create!(
user: #admin0,
post: #post3 & #post5 & #post6 & #post8 & #post9,
comment: #comment1,
username: #admin0.username
)
or NotNullViolation: ERROR: null value in column "comment_id" violates not-null constraint if set up like so:
class Like < ApplicationRecord
belongs_to :comment, optional: true
belongs_to :post, optional: true
belongs_to :user
validates :user_id, uniqueness: {scope: :post_id}
validates :user_id, uniqueness: {scope: :comment_id}
end
#like0 = Like.create!(
user: #admin0,
post: #post3,
comment: #comment1,
username: #admin0.username
)
my question is how can I better set up the relationship between these 4 models so as to not get these errors?