Install rails_admin and devise. Start setting it up.

Gemfile.lock

@@ -42,6 +42,10 @@ GEM
       globalid (>= 0.3.6)
     activemodel (6.0.3.2)
       activesupport (= 6.0.3.2)
+    activemodel-serializers-xml (1.0.2)
+      activemodel (> 5.x)
+      activesupport (> 5.x)
+      builder (~> 3.1)
     activerecord (6.0.3.2)
       activemodel (= 6.0.3.2)
       activesupport (= 6.0.3.2)
@@ -58,6 +62,7 @@ GEM
       zeitwerk (~> 2.2, >= 2.2.2)
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
+    bcrypt (3.1.15)
     bindex (0.8.1)
     bootsnap (1.4.8)
       msgpack (~> 1.0)
@@ -74,15 +79,42 @@ GEM
     childprocess (3.0.0)
     concurrent-ruby (1.1.7)
     crass (1.0.6)
+    devise (4.7.2)
+      bcrypt (~> 3.0)
+      orm_adapter (~> 0.1)
+      railties (>= 4.1.0)
+      responders
+      warden (~> 1.2.3)
     erubi (1.9.0)
     ffi (1.13.1)
     ffi (1.13.1-x64-mingw32)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
+    haml (5.1.2)
+      temple (>= 0.8.0)
+      tilt
     i18n (1.8.5)
       concurrent-ruby (~> 1.0)
     jbuilder (2.10.0)
       activesupport (>= 5.0.0)
+    jquery-rails (4.4.0)
+      rails-dom-testing (>= 1, < 3)
+      railties (>= 4.2.0)
+      thor (>= 0.14, < 2.0)
+    jquery-ui-rails (6.0.1)
+      railties (>= 3.2.16)
+    kaminari (1.2.1)
+      activesupport (>= 4.1.0)
+      kaminari-actionview (= 1.2.1)
+      kaminari-activerecord (= 1.2.1)
+      kaminari-core (= 1.2.1)
+    kaminari-actionview (1.2.1)
+      actionview
+      kaminari-core (= 1.2.1)
+    kaminari-activerecord (1.2.1)
+      activerecord
+      kaminari-core (= 1.2.1)
+    kaminari-core (1.2.1)
     listen (3.2.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -100,17 +132,22 @@ GEM
     minitest (5.14.1)
     msgpack (1.3.3)
     msgpack (1.3.3-x64-mingw32)
+    nested_form (0.3.2)
     nio4r (2.5.2)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
     nokogiri (1.10.10-x64-mingw32)
       mini_portile2 (~> 2.4.0)
+    orm_adapter (0.5.0)
     pg (1.2.3)
     pg (1.2.3-x64-mingw32)
     public_suffix (4.0.5)
     puma (4.3.5)
       nio4r (~> 2.0)
     rack (2.2.3)
+    rack-pjax (1.1.0)
+      nokogiri (~> 1.5)
+      rack (>= 1.1)
     rack-proxy (0.6.5)
       rack
     rack-test (1.1.0)
@@ -135,6 +172,18 @@ GEM
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.3.0)
       loofah (~> 2.3)
+    rails_admin (2.0.2)
+      activemodel-serializers-xml (>= 1.0)
+      builder (~> 3.1)
+      haml (>= 4.0, < 6)
+      jquery-rails (>= 3.0, < 5)
+      jquery-ui-rails (>= 5.0, < 7)
+      kaminari (>= 0.14, < 2.0)
+      nested_form (~> 0.3)
+      rack-pjax (>= 0.7)
+      rails (>= 5.0, < 7)
+      remotipart (~> 1.3)
+      sassc-rails (>= 1.3, < 3)
     railties (6.0.3.2)
       actionpack (= 6.0.3.2)
       activesupport (= 6.0.3.2)
@@ -146,6 +195,10 @@ GEM
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     regexp_parser (1.7.1)
+    remotipart (1.4.4)
+    responders (3.0.1)
+      actionpack (>= 5.0)
+      railties (>= 5.0)
     rubyzip (2.3.0)
     sass-rails (6.0.0)
       sassc-rails (~> 2.1, >= 2.1.1)
@@ -173,6 +226,7 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
+    temple (0.8.2)
     thor (1.0.1)
     thread_safe (0.3.6)
     tilt (2.0.10)
@@ -183,6 +237,8 @@ GEM
       thread_safe (~> 0.1)
     tzinfo-data (1.2020.1)
       tzinfo (>= 1.0.0)
+    warden (1.2.8)
+      rack (>= 2.0.6)
     web-console (4.0.4)
       actionview (>= 6.0.0)
       activemodel (>= 6.0.0)
@@ -211,11 +267,13 @@ DEPENDENCIES
   bootsnap (>= 1.4.2)
   byebug
   capybara (>= 2.15)
+  devise (~> 4.7)
   jbuilder (~> 2.7)
   listen (~> 3.2)
   pg (>= 0.18, < 2.0)
   puma (~> 4.1)
   rails (~> 6.0.3, >= 6.0.3.2)
+  rails_admin (~> 2.0)
   sass-rails (>= 6)
   selenium-webdriver
   spring