Add users management to site settings (#126)

Gemfile.lock

@@ -58,16 +58,6 @@ GEM
       zeitwerk (~> 2.2, >= 2.2.2)
     addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
-    administrate (0.16.0)
-      actionpack (>= 5.0)
-      actionview (>= 5.0)
-      activerecord (>= 5.0)
-      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)
     babel-source (5.8.35)
     babel-transpiler (0.7.0)
       babel-source (>= 4.0, < 6)
@@ -91,8 +81,6 @@ GEM
     concurrent-ruby (1.1.10)
     connection_pool (2.2.5)
     crass (1.0.6)
-    datetime_picker_rails (0.0.7)
-      momentjs-rails (>= 2.8.1)
     devise (4.7.3)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
@@ -117,10 +105,6 @@ GEM
     jbuilder (2.11.5)
       actionview (>= 5.0.0)
       activesupport (>= 5.0.0)
-    jquery-rails (4.5.0)
-      rails-dom-testing (>= 1, < 3)
-      railties (>= 4.2.0)
-      thor (>= 0.14, < 2.0)
     kaminari (1.2.2)
       activesupport (>= 4.1.0)
       kaminari-actionview (= 1.2.2)
@@ -148,8 +132,6 @@ GEM
     mini_mime (1.1.2)
     mini_portile2 (2.8.0)
     minitest (5.15.0)
-    momentjs-rails (2.29.1.1)
-      railties (>= 3.1)
     msgpack (1.5.2)
     nio4r (2.5.8)
     nokogiri (1.13.6)
@@ -239,15 +221,6 @@ 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 (4.1.0)
       childprocess (>= 0.5, < 5.0)
       rexml (~> 3.2, >= 3.2.5)
@@ -297,7 +270,6 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  administrate (= 0.16.0)
   bootsnap (>= 1.4.2)
   byebug
   capybara (>= 2.15)
@@ -314,7 +286,6 @@ DEPENDENCIES
   react-rails (~> 2.6.0)
   rspec-rails (~> 3.8.2)
   sass-rails (~> 5)
-  sassc (= 2.1.0)
   selenium-webdriver
   spring
   spring-watcher-listen (~> 2.0.0)