Add net-smtp as gem

Gemfile.lock

@@ -114,6 +114,7 @@ GEM
       irb (>= 1.3.6)
       reline (>= 0.2.7)
     diff-lcs (1.5.0)
+    digest (3.1.0)
     erubi (1.10.0)
     ffi (1.15.4)
     globalid (1.0.0)
@@ -127,6 +128,7 @@ GEM
       actionpack (>= 6.0.0)
       railties (>= 6.0.0)
     io-console (0.5.10)
+    io-wait (0.2.1)
     irb (1.4.1)
       reline (>= 0.3.0)
     jbuilder (2.11.5)
@@ -145,6 +147,13 @@ GEM
     mini_portile2 (2.6.1)
     minitest (5.15.0)
     msgpack (1.4.2)
+    net-protocol (0.1.2)
+      io-wait
+      timeout
+    net-smtp (0.3.1)
+      digest
+      net-protocol
+      timeout
     nio4r (2.5.8)
     nokogiri (1.12.5)
       mini_portile2 (~> 2.6.1)
@@ -226,6 +235,7 @@ GEM
     stimulus-rails (1.0.2)
       railties (>= 6.0.0)
     thor (1.1.0)
+    timeout (0.2.0)
     turbo-rails (1.0.0)
       actionpack (>= 6.0.0)
       railties (>= 6.0.0)
@@ -263,6 +273,7 @@ DEPENDENCIES
   image_processing (~> 1.2)
   importmap-rails
   jbuilder
+  net-smtp
   pg (~> 1.1)
   puma (~> 5.0)
   rack-mini-profiler