Remove validation from username

app/models/user.rb

@@ -13,7 +13,7 @@ class User < ApplicationRecord
   has_many :phone_numbers, foreign_key: :owner_id, dependent: :destroy
   has_many :oauth_applications, class_name: "Doorkeeper::Application", as: :owner
 
-  validates :username, uniqueness: {case_sensitive: false}, format: {with: /\A[a-z0-9_-]+\z/i}, presence: true
+  validates :username, uniqueness: {case_sensitive: false}, presence: true
   validates :twitter, format: {with: /\A[A-Za-z0-9_]{1,15}\z/}, allow_blank: true
   validates :url, format: {with: /\A(http|https):\/\/[a-z0-9]+([-.]{1}[a-z0-9]+)*\.[a-z-]{2,63}(:[0-9]{1,5})?(\/.*)?\z/ix}, allow_blank: true
   validates :name, presence: true