Add admin panel and make it work for user resource

Gemfile.lock

@@ -9,6 +9,23 @@ GIT
       responders
       warden (~> 1.2.3)
 
+GIT
+  remote: https://github.com/thoughtbot/administrate.git
+  revision: fcf46ae4e6989ceb1b091791fec754a67da0f32c
+  specs:
+    administrate (0.11.0)
+      actionpack (>= 4.2)
+      actionview (>= 4.2)
+      activejob (>= 4.2)
+      activerecord (>= 4.2)
+      autoprefixer-rails (>= 6.0)
+      datetime_picker_rails (~> 0.0.7)
+      jquery-rails (>= 4.0)
+      kaminari (>= 1.0)
+      momentjs-rails (~> 2.8)
+      sassc-rails (~> 2.1)
+      selectize-rails (~> 0.6)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -69,6 +86,8 @@ GEM
       zeitwerk (~> 2.1, >= 2.1.8)
     addressable (2.6.0)
       public_suffix (>= 2.0.2, < 4.0)
+    autoprefixer-rails (9.6.1)
+      execjs
     bcrypt (3.1.13)
     bindex (0.8.1)
     bootsnap (1.4.4)
@@ -87,8 +106,11 @@ GEM
       rake (< 13.0)
     concurrent-ruby (1.1.5)
     crass (1.0.4)
+    datetime_picker_rails (0.0.7)
+      momentjs-rails (>= 2.8.1)
     diff-lcs (1.3)
     erubi (1.8.0)
+    execjs (2.7.0)
     factory_bot (5.0.2)
       activesupport (>= 4.2.0)
     factory_bot_rails (5.0.2)
@@ -101,6 +123,22 @@ GEM
       concurrent-ruby (~> 1.0)
     jbuilder (2.9.1)
       activesupport (>= 4.2.0)
+    jquery-rails (4.3.5)
+      rails-dom-testing (>= 1, < 3)
+      railties (>= 4.2.0)
+      thor (>= 0.14, < 2.0)
+    kaminari (1.1.1)
+      activesupport (>= 4.1.0)
+      kaminari-actionview (= 1.1.1)
+      kaminari-activerecord (= 1.1.1)
+      kaminari-core (= 1.1.1)
+    kaminari-actionview (1.1.1)
+      actionview
+      kaminari-core (= 1.1.1)
+    kaminari-activerecord (1.1.1)
+      activerecord
+      kaminari-core (= 1.1.1)
+    kaminari-core (1.1.1)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -117,6 +155,8 @@ GEM
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
+    momentjs-rails (2.20.1)
+      railties (>= 3.1)
     msgpack (1.3.1)
     nio4r (2.4.0)
     nokogiri (1.10.4)
@@ -194,6 +234,15 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
+    sassc (2.1.0)
+      ffi (~> 1.9)
+    sassc-rails (2.1.2)
+      railties (>= 4.0.0)
+      sassc (>= 2.0)
+      sprockets (> 3.0)
+      sprockets-rails
+      tilt
+    selectize-rails (0.12.6)
     selenium-webdriver (3.142.3)
       childprocess (>= 0.5, < 2.0)
       rubyzip (~> 1.2, >= 1.2.2)
@@ -242,6 +291,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  administrate!
   bootsnap (>= 1.4.2)
   byebug
   capybara (>= 2.15)