diff --git a/Gemfile b/Gemfile
index de74de092e..5ed4060f17 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,8 +11,7 @@ gem 'rails-i18n'
 # released.
 gem 'mail', '= 2.8.1'
 
-# Use sqlite3 as the database for Active Record
-gem 'sqlite3'
+gem 'pg'
 # Use Puma as the app server
 gem 'puma'
 # Use jquery as the JavaScript library
diff --git a/Gemfile.lock b/Gemfile.lock
index bc4500d7e6..228e70a540 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -279,6 +279,7 @@ GEM
       racc (~> 1.4)
     orm_adapter (0.5.0)
     pagy (6.2.0)
+    pg (1.5.4)
     psych (5.1.1.1)
       stringio
     public_suffix (5.0.3)
@@ -462,6 +463,7 @@ DEPENDENCIES
   minitest
   minitest-ci
   pagy
+  pg
   puma
   pundit
   rails (~> 7.1.1)
@@ -472,7 +474,6 @@ DEPENDENCIES
   simplecov
   spring
   sprockets
-  sqlite3
   terser
   turbolinks
   tzinfo-data
diff --git a/README.md b/README.md
index 7da8ec41ab..35f0373606 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ rm config/credentials.yml.enc
 export EDITOR=vim
 # paste credentials.yml.sample or skip
 bin/rails credentials:edit
+bin/rails db:create
 bin/rails test:all
 ```
 
diff --git a/config/database.yml.sample b/config/database.yml.sample
index 78fcfad758..ad0dbbabc4 100644
--- a/config/database.yml.sample
+++ b/config/database.yml.sample
@@ -1,13 +1,13 @@
 ---
 default: &default
-  adapter: sqlite3
+  adapter: postgresql
   pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
   timeout: 5000
 
 development:
   primary:
     <<: *default
-    database: storage/oauth2id_dev.sqlite3
+    database: <%= ENV.fetch("OAUTH2ID_DEV_DB_NAME") { 'oauth2id_dev' } %>
 
 # Warning: The database defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
@@ -15,9 +15,12 @@ development:
 test:
   primary:
     <<: *default
-    database: storage/oauth2id_test.sqlite3
+    database: <%= ENV.fetch("OAUTH2ID_TEST_DB_NAME") { 'oauth2id_test' } %>
 
 production:
   primary:
     <<: *default
-    database: storage/oauth2id_prod.sqlite3
+    database: <%= ENV.fetch("OAUTH2ID_DB_NAME") { 'oauth2id_prod' } %>
+    username: <%= ENV.fetch("OAUTH2ID_DB_USERNAME") { '' } %>
+    password: <%= ENV.fetch("OAUTH2ID_DB_PASSWORD") { '' } %>
+    host: <%= ENV.fetch("OAUTH2ID_DB_HOST") { '' } %>