Introduce better debugging tools in development

Gemfile

@@ -67,6 +67,8 @@ group :development do
   gem 'capistrano-rails'
   # gem 'capistrano-rvm'
   gem 'capistrano3-puma'
+  gem 'better_errors'
+  gem 'binding_of_caller'
 end
 
 group :development, :test do

Gemfile.lock

@@ -45,6 +45,12 @@ GEM
       execjs
     awesome_print (1.7.0)
     bcrypt (3.1.11)
+    better_errors (2.1.1)
+      coderay (>= 1.0.0)
+      erubis (>= 2.6.6)
+      rack (>= 0.9.0)
+    binding_of_caller (0.7.2)
+      debug_inspector (>= 0.0.1)
     bootstrap-sass (3.3.7)
       autoprefixer-rails (>= 5.2.1)
       sass (>= 3.3.4)
@@ -94,6 +100,7 @@ GEM
     concurrent-ruby (1.0.2)
     copy_carrierwave_file (1.3.0)
       carrierwave (>= 0.9)
+    debug_inspector (0.0.2)
     devise (4.2.0)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
@@ -373,6 +380,8 @@ PLATFORMS
 DEPENDENCIES
   autoprefixer-rails
   awesome_print
+  better_errors
+  binding_of_caller
   bootstrap-sass
   bootstrap-sass-extras
   bootswatch-rails