Rather than using a Postgres string array and doing selection in Ruby, utilize ActiveRecord and SQL to only retrieve the relevant data in the first place. Feedback on https://github.com/ros3bud/Meet2Talk/tree/54f02428ada5e913c03b2b58160a19ea6fd7e7f8.

add_skills_users_join_table.rb

# db/migration/2013_add_skills_users_join_table.rb

class AddSkillsUsersJoinTable < ActiveRecord::Migration
  # see http://guides.rubyonrails.org/association_basics.html#the-has-and-belongs-to-many-association
  def change
    create_table :skills_users do |t|
      t.belongs_to :skill
      t.belongs_to :user
    end
  end
end

skill.rb

# app/models/skill.rb

class Skill < ActiveRecord::Base
  has_and_belongs_to_many :users
  
  def self.list
    # see http://guides.rubyonrails.org/active_record_querying.html#pluck
    pluck(:name)
  end
end

user.rb

# app/models/user.rb

class User < ActiveRecord::Base
  # see http://guides.rubyonrails.org/association_basics.html#the-has-and-belongs-to-many-association
  has_and_belongs_to_many :skills 
         
  def self.with_skill(skill_name)
    # see http://guides.rubyonrails.org/active_record_querying.html#eager-loading-associations
    # see http://guides.rubyonrails.org/active_record_querying.html#hash-conditions
    includes(:skills).where(skill: { name: skill_name })
  end
end