SQLite3::SQLException: no such column (Ruby on Rails) - ruby-on-rails

Question

So I'm trying to use appointments gem (http://www.rubydoc.info/gems/appointments/1.3.3). I've done exactly as that document says and I keep getting the following error:
ActiveRecord::StatementInvalid in AppointmentsController#index
SQLite3::SQLException: no such column: appointments.date: SELECT "appointments".* FROM "appointments" WHERE "appointments"."date" IS NULL
app/controllers/appointments_controller.rb:6:in `index'
schema.rb
ActiveRecord::Schema.define(version: 20180402162908) do
create_table "appointments", force: :cascade do |t|
t.datetime "appointment_time"
t.integer "duration"
t.float "price"
t.integer "user_id"
t.integer "client_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "appointments", ["client_id"], name: "index_appointments_on_client_id"
add_index "appointments", ["user_id"], name: "index_appointments_on_user_id"
create_table "clients", force: :cascade do |t|
t.string "name"
t.string "phone_number"
t.string "email"
t.string "address"
t.integer "user_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "clients", ["user_id"], name: "index_clients_on_user_id"
create_table "services", force: :cascade do |t|
t.string "name"
t.string "description"
t.float "price"
t.integer "duration"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "users", force: :cascade do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", default: 0, null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "users", ["email"], name: "index_users_on_email", unique: true
add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
end
appointments_controller.rb
class AppointmentsController < ApplicationController
def index
date_from_ajax = params[:matched_date]
reduce = Appointment.where(:date => date_from_ajax)
hour_on_date = reduce.collect {|x| x.hour}
#new_dates = hour_on_date
render :layout => false
end
def new
#appointments = Appointment.create
respond_to do |format|
format.html
format.js
end
end
def create
#appointment = Appointment.create(params[:appointments])
if #appointment.save
redirect_to new_appointment_path
else
err = ''
#appointment.errors.full_messages.each do |m|
err << m
end
redirect_to new_appointment_path, :flash => { :alert => "#{err}, please try again" }
end
end
private
def appointment_params
params.require(:appointment).permit(:date, :hour, :done)
end
end
appointments.rb
class Appointment < ActiveRecord::Base
validates :date, :presence => true
validates :hour, :presence => true,
:uniqueness => {:scope => :date}
end
Is there any chance someone could help me with this.
Thanks in advance :)
(Rails version: 4.2.6)