Update backbonejs, switch to rails-assets source

Gemfile

@@ -85,7 +85,6 @@ gem "entypo-rails", "3.0.0.pre.rc2"
 
 # JavaScript
 
-gem "backbone-on-rails", "1.2.0.0"
 gem "handlebars_assets", "0.23.1"
 gem "jquery-rails",      "4.2.1"
 gem "jquery-ui-rails",   "5.0.5"
@@ -103,6 +102,8 @@ source "https://rails-assets.org" do
   gem "rails-assets-markdown-it-sub",                     "1.0.0"
   gem "rails-assets-markdown-it-sup",                     "1.0.0"
   gem "rails-assets-highlightjs",                         "9.7.0"
+
+  gem "rails-assets-backbone",                            "1.3.3"
   gem "rails-assets-bootstrap-markdown",                  "2.10.0"
   gem "rails-assets-corejs-typeahead",                    "1.0.1"
   gem "rails-assets-fineuploader-dist",                   "5.11.0"

Gemfile.lock

@@ -58,11 +58,6 @@ GEM
     attr_required (1.0.1)
     autoprefixer-rails (6.5.1)
       execjs
-    backbone-on-rails (1.2.0.0)
-      eco
-      ejs
-      jquery-rails
-      railties
     bcrypt (3.1.11)
     bindata (2.3.1)
     bootstrap-sass (3.3.7)
@@ -191,12 +186,6 @@ GEM
     docile (1.1.5)
     domain_name (0.5.20160615)
       unf (>= 0.0.5, < 1.0.0)
-    eco (1.0.0)
-      coffee-script
-      eco-source
-      execjs
-    eco-source (1.1.0.rc.1)
-    ejs (1.1.1)
     entypo-rails (3.0.0.pre.rc2)
       railties (>= 4.1, <= 5)
     equalizer (0.0.10)
@@ -641,6 +630,8 @@ GEM
       railties (= 4.2.7.1)
       sprockets-rails
     rails-assets-autosize (3.0.20)
+    rails-assets-backbone (1.3.3)
+      rails-assets-underscore (>= 1.8.3)
     rails-assets-blueimp-gallery (2.21.3)
     rails-assets-bootstrap (3.3.7)
       rails-assets-jquery (>= 1.9.1, < 4)
@@ -681,6 +672,7 @@ GEM
     rails-assets-markdown-it-sub (1.0.0)
     rails-assets-markdown-it-sup (1.0.0)
     rails-assets-perfect-scrollbar (0.6.12)
+    rails-assets-underscore (1.8.3)
     rails-deprecated_sanitizer (1.0.3)
       activesupport (>= 4.2.0.alpha)
     rails-dom-testing (1.0.7)
@@ -922,7 +914,6 @@ DEPENDENCIES
   addressable (= 2.4.0)
   asset_sync (= 1.1.0)
   autoprefixer-rails (= 6.5.1)
-  backbone-on-rails (= 1.2.0.0)
   bootstrap-sass (= 3.3.7)
   bootstrap-switch-rails (= 3.3.3)
   capybara (= 2.10.1)
@@ -998,6 +989,7 @@ DEPENDENCIES
   rack-ssl (= 1.4.1)
   rails (= 4.2.7.1)
   rails-assets-autosize (= 3.0.20)!
+  rails-assets-backbone (= 1.3.3)!
   rails-assets-blueimp-gallery (= 2.21.3)!
   rails-assets-bootstrap-markdown (= 2.10.0)!
   rails-assets-corejs-typeahead (= 1.0.1)!