Fix format of database migrations

db/migrate/20141117201926_create_users.rb

@@ -1,4 +1,4 @@
-class CreateUsers < ActiveRecord::Migration
+class CreateUsers < ActiveRecord::Migration[4.2]
   def change
     create_table :users do |t|
       t.string :email

db/migrate/20150413193656_create_papers.rb

@@ -1,4 +1,4 @@
-class CreatePapers < ActiveRecord::Migration
+class CreatePapers < ActiveRecord::Migration[4.2]
   def change
     create_table :papers do |t|
       t.string :name

db/migrate/20150517152218_create_importers.rb

@@ -1,4 +1,4 @@
-class CreateImporters < ActiveRecord::Migration
+class CreateImporters < ActiveRecord::Migration[4.2]
   def change
     create_table :importers do |t|
       t.string :url

db/migrate/20151010070158_create_paper_searches.rb

@@ -1,4 +1,4 @@
-class CreatePaperSearches < ActiveRecord::Migration
+class CreatePaperSearches < ActiveRecord::Migration[4.2]
   def change
     create_table :paper_searches do |t|
       t.string :query

db/schema.rb

@@ -1,4 +1,3 @@
-# encoding: UTF-8
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
@@ -39,19 +38,17 @@ ActiveRecord::Schema.define(version: 20151010070158) do
     t.text "content"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["body"], name: "index_papers_on_body"
+    t.index ["originator"], name: "index_papers_on_originator"
+    t.index ["reference", "body"], name: "index_papers_on_reference_and_body", unique: true
+    t.index ["reference"], name: "index_papers_on_reference"
   end
 
-  add_index "papers", ["body"], name: "index_papers_on_body"
-  add_index "papers", ["originator"], name: "index_papers_on_originator"
-  add_index "papers", ["reference", "body"], name: "index_papers_on_reference_and_body", unique: true
-  add_index "papers", ["reference"], name: "index_papers_on_reference"
-
   create_table "users", force: :cascade do |t|
     t.string "email"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["email"], name: "index_users_on_email", unique: true
   end
 
-  add_index "users", ["email"], name: "index_users_on_email", unique: true
-
 end