Switch from MySQL to SQLite for simpler deployment

Dockerfile

@@ -1,7 +1,7 @@
 FROM ruby:3.2-slim
 
 RUN apt-get update -qq && \
-    apt-get install -y build-essential libmariadb-dev libyaml-dev git curl && \
+    apt-get install -y build-essential libsqlite3-dev libyaml-dev git curl && \
     rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app

Gemfile

@@ -3,7 +3,7 @@ source 'https://rubygems.org'
 ruby '>= 3.2.0'
 
 gem 'rails', '~> 7.1.0'
-gem 'mysql2', '~> 0.5'
+gem 'sqlite3', '~> 1.4'
 gem 'puma', '~> 6.0'
 gem 'bootsnap', require: false
 

Gemfile.lock

@@ -118,12 +118,11 @@ GEM
       net-smtp
     marcel (1.1.0)
     mini_mime (1.1.5)
+    mini_portile2 (2.8.9)
     minitest (6.0.1)
       prism (~> 1.5)
     msgpack (1.8.0)
     mutex_m (0.3.0)
-    mysql2 (0.5.7)
-      bigdecimal
     net-imap (0.6.2)
       date
       net-protocol
@@ -207,6 +206,8 @@ GEM
     reline (0.6.3)
       io-console (~> 0.5)
     securerandom (0.4.1)
+    sqlite3 (1.7.3)
+      mini_portile2 (~> 2.8.0)
     stringio (3.2.0)
     thor (1.5.0)
     timeout (0.6.0)
@@ -233,9 +234,12 @@ PLATFORMS
 DEPENDENCIES
   bootsnap
   debug
-  mysql2 (~> 0.5)
   puma (~> 6.0)
   rails (~> 7.1.0)
+  sqlite3 (~> 1.4)
+
+RUBY VERSION
+   ruby 3.4.7p58
 
 BUNDLED WITH
    2.6.9

config/database.yml

@@ -1,20 +1,16 @@
 default: &default
-  adapter: mysql2
+  adapter: sqlite3
-  encoding: utf8mb4
   pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
-  username: <%= ENV.fetch("DB_USERNAME") { "root" } %>
+  timeout: 5000
-  password: <%= ENV.fetch("DB_PASSWORD") { "" } %>
-  host: <%= ENV.fetch("DB_HOST") { "localhost" } %>
-  port: <%= ENV.fetch("DB_PORT") { 3306 } %>
 
 development:
   <<: *default
-  database: rails_test_development
+  database: db/development.sqlite3
 
 test:
   <<: *default
-  database: rails_test_test
+  database: db/test.sqlite3
 
 production:
   <<: *default
-  database: <%= ENV.fetch("DB_NAME") { "rails_test_production" } %>
+  database: db/production.sqlite3