Update

Gemfile

@@ -13,7 +13,7 @@ gem 'rails', '~> 5.1.0'
 #gem 'mysql2', '>= 0.3.18', '< 0.5'
 
 #Use PosgreSQL
-#gem 'pg'
+gem 'pg'
 
 # redis server for cable
 # gem 'redis', '~> 3.0'
@@ -94,4 +94,4 @@ gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
 
 gem 'httparty', '~> 0.15.5'
 
-gem 'bootstrap-datepicker-rails'
+gem 'bootstrap-datepicker-rails'

Gemfile.lock

@@ -123,6 +123,7 @@ GEM
     nokogiri (1.7.2)
       mini_portile2 (~> 2.1.0)
     pdf-core (0.7.0)
+    pg (0.20.0)
     prawn (2.2.2)
       pdf-core (~> 0.7.0)
       ttfunk (~> 1.5)
@@ -258,7 +259,6 @@ DEPENDENCIES
   kaminari!
   listen (~> 3.0.5)
   pg
-  mysql2 (>= 0.3.18, < 0.5)
   prawn
   prawn-table
   puma (~> 3.0)