diff --git a/.gitignore b/.gitignore
index 1b95341e..e197be3c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,3 +23,4 @@ coverage/*
 public/upload*
 upload*
 .byebug_history
+docker-compose.yml
\ No newline at end of file
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 00000000..9193595c
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,19 @@
+FROM opensuse/leap:15.1
+
+# This includes several packages (like WebKit, xvfb or liberation-fonts)
+# That are only needed to run the automated tests and wouldn't be relevant
+# in a production environment.
+RUN zypper --gpg-auto-import-keys --non-interactive in --no-recommends \
+  ruby ruby-devel ruby2.5-rubygem-bundler libxml2-devel libxslt-devel \
+  postgresql-devel sqlite3-devel libmariadb-devel \
+  libQt5WebKit5 libQt5WebKit5-devel libQt5WebKitWidgets5 libQt5WebKitWidgets-devel \
+  xvfb-run which liberation-fonts gcc gcc-c++ make tar gzip patch timezone && \
+  zypper clean -a
+
+RUN mkdir /app
+WORKDIR /app
+COPY . /app
+ENV QMAKE=/usr/bin/qmake-qt5
+RUN bundle install
+
+CMD ["rails", "server", "-b", "0.0.0.0"]
diff --git a/Gemfile b/Gemfile
index 7f1d2bb9..14b5c468 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ gem 'responders', '~> 2.0'
 # Choose your weapon
 gem 'sqlite3', '~> 1.3.13'
 # gem 'pg', '~> 0.21'
-# gem 'mysql2', '~> 0.3.13'
+# gem 'mysql2', '~> 0.4.10'
 
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 4.0.0'
diff --git a/README.md b/README.md
index 7e4b01f0..e4ba0c01 100644
--- a/README.md
+++ b/README.md
@@ -24,12 +24,17 @@ name).
 
 ## Requirements
 
-* Ruby >= 1.9
+* Ruby >= 2.4
 * Any Rails supported database system: PosgreSQL, SQLite3, MariaDB, MySQL...
 
 ## Installation
 Please refer to [INSTALL](doc/INSTALL.md) documentation file
 
+## Development
+To simplify the process of setting up a development environment, this repository
+includes some `docker-compose` configuration examples. Check the
+[DOCKER](doc/DOCKER.md) documentation file.
+
 ## Contact
 
 Ancor González Sosa
diff --git a/app/controllers/events_controller.rb b/app/controllers/events_controller.rb
index 36a07f2a..5ccdd90d 100644
--- a/app/controllers/events_controller.rb
+++ b/app/controllers/events_controller.rb
@@ -10,7 +10,8 @@ def participants
       { label: @event.name, url: event_path(@event) },
       { label: 'participants' }
     ]
-    @requests = @event.travel_sponsorships.includes(:user).group(:user_id).accessible_by(current_ability)
+    @requests = @event.travel_sponsorships.eager_load(:user).order('lower(users.nickname)').accessible_by(current_ability)
+    @requests.uniq!(&:user_id)
   end
 
   protected
diff --git a/app/helpers/events_helper.rb b/app/helpers/events_helper.rb
index fd379392..bcfcaca3 100644
--- a/app/helpers/events_helper.rb
+++ b/app/helpers/events_helper.rb
@@ -14,7 +14,7 @@ def event_title_line(event)
   def users_for_event(state)
     requests = @event.travel_sponsorships.includes(:user).accessible_by(current_ability)
     requests = requests.where(state: state) if state != 'all'
-    requests.distinct.pluck('users.email')
+    requests.distinct.order('users.email').pluck('users.email')
   end
 
   def state_label(state)
diff --git a/app/models/event_organizer.rb b/app/models/event_organizer.rb
index 59d6cb5f..19a5df06 100644
--- a/app/models/event_organizer.rb
+++ b/app/models/event_organizer.rb
@@ -9,6 +9,6 @@ class EventOrganizer < ActiveRecord::Base
   validates :user_id, uniqueness: { scope: :event_id, message: 'Already an event organizer for this event' }
 
   def self.autocomplete_users(term)
-    User.order(:nickname).where('nickname like ? or email like ?', "%#{term}%", "%#{term}%").pluck(:nickname, :email)
+    User.order('lower(nickname)').where('nickname like ? or email like ?', "%#{term}%", "%#{term}%").pluck(:nickname, :email)
   end
 end
diff --git a/doc/DOCKER.md b/doc/DOCKER.md
new file mode 100644
index 00000000..3b8a5f33
--- /dev/null
+++ b/doc/DOCKER.md
@@ -0,0 +1,37 @@
+# Using Docker to Develop TSP
+
+This repository includes a `Dockerfile` and a set of `docker-compose` configuration examples in
+order to simplify the process of setting up a development environment.
+
+Given that you have `docker` and `docker-compose` installed, the process should be pretty
+straighforward.
+
+1. Select a `docker-compose` configuration file from the `docker/` directory and copy it as
+   `docker-compose.yml`. For instance, to run the application using a PostgreSQL database:
+
+        cp docker/docker-compose.development.postgresql docker-compose.yml
+
+2. Uncomment the gem for your favorite database driver from the `Gemfile`.
+3. Copy the database configuration from `docker/` for your database. For instance,
+   to use PostgreSQL:
+
+        cp docker/database.postgresql.yml config/database.yml
+
+3. Build the image:
+
+        docker-compose build
+
+4. Now you should be able to set up the database:
+
+        docker-compose run --rm web rake db:setup
+
+5. (Optional) Run the testsuite to find out whether the application works.
+
+        docker-compose run --rm web xvfb-run -a rake spec
+
+6. And, now, you can start the application:
+
+        docker-compose up
+
+For now on, you will need to rebuild the image whenever you change the `Gemfile` or `Gemfile.lock`
+files.
diff --git a/docker/database.mysql.yml b/docker/database.mysql.yml
new file mode 100644
index 00000000..b79177ad
--- /dev/null
+++ b/docker/database.mysql.yml
@@ -0,0 +1,25 @@
+# Ensure the MySQL connector gem is defined in your Gemfile
+# gem 'mysql2'
+
+# Warning: this proposes the usage of the root user with no password.
+# That's done for simplicity because this docker manifest is only meant for
+# development purposes and, for that, a user with privileges to create and
+# destroy databases is very convenient.
+# NEVER use such setup in a production system.
+
+development:
+  adapter: mysql2
+  database: tsp_development
+  host: db
+  username: root
+  password:
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  adapter: mysql2
+  database: tsp_test
+  host: db
+  username: root
+  password:
diff --git a/docker/database.postgresql.yml b/docker/database.postgresql.yml
new file mode 100644
index 00000000..f7261198
--- /dev/null
+++ b/docker/database.postgresql.yml
@@ -0,0 +1,29 @@
+# Ensure the PostgreSQL connector gem is defined in your Gemfile
+# gem 'pg'
+
+# Warning: this proposes the usage of the postgres superuser with no password.
+# That's done for simplicity because this docker manifest is only meant for
+# development purposes and, for that, a user with privileges to create and
+# destroy databases is very convenient.
+# NEVER use such setup in a production system.
+
+development:
+  adapter: postgresql
+  encoding: unicode
+  database: tsp_development
+  pool: 5
+  host: db
+  username: postgres
+  password:
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  adapter: postgresql
+  encoding: unicode
+  database: tsp_test
+  pool: 5
+  host: db
+  username: postgres
+  password:
diff --git a/docker/database.sqlite.yml b/docker/database.sqlite.yml
new file mode 100644
index 00000000..1902f924
--- /dev/null
+++ b/docker/database.sqlite.yml
@@ -0,0 +1,19 @@
+# SQLite version 3.x
+#   gem install sqlite3
+#
+#   Ensure the SQLite 3 gem is defined in your Gemfile
+#   gem 'sqlite3'
+development:
+  adapter: sqlite3
+  database: db/development.sqlite3
+  pool: 5
+  timeout: 5000
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  adapter: sqlite3
+  database: db/test.sqlite3
+  pool: 5
+  timeout: 5000
diff --git a/docker/docker-compose.development.mysql.yml b/docker/docker-compose.development.mysql.yml
new file mode 100644
index 00000000..c671df11
--- /dev/null
+++ b/docker/docker-compose.development.mysql.yml
@@ -0,0 +1,18 @@
+version: '3'
+services:
+  web:
+    image: tsp:latest
+    build: .
+    volumes:
+      - .:/app
+    ports:
+      - "3000:3000"
+    depends_on:
+      - db
+  db:
+    image: mariadb:10.2
+    restart: always
+    environment:
+      MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
+      # MYSQL_ROOT_PASSWORD: "tsp:secret"
+
diff --git a/docker/docker-compose.development.postgresql.yml b/docker/docker-compose.development.postgresql.yml
new file mode 100644
index 00000000..0d43b858
--- /dev/null
+++ b/docker/docker-compose.development.postgresql.yml
@@ -0,0 +1,14 @@
+version: '3'
+services:
+  web:
+    image: tsp:latest
+    build: .
+    volumes:
+      - .:/app
+    ports:
+      - "3000:3000"
+    depends_on:
+      - db
+  db:
+    image: postgres:9.6
+    restart: always
diff --git a/docker/docker-compose.development.sqlite3.yml b/docker/docker-compose.development.sqlite3.yml
new file mode 100644
index 00000000..a0cd8572
--- /dev/null
+++ b/docker/docker-compose.development.sqlite3.yml
@@ -0,0 +1,9 @@
+version: '3'
+services:
+  web:
+    image: tsp:latest
+    build: .
+    volumes:
+      - .:/app
+    ports:
+      - "3000:3000"
diff --git a/spec/features/event_emails_spec.rb b/spec/features/event_emails_spec.rb
index 1873d955..f112f8ae 100644
--- a/spec/features/event_emails_spec.rb
+++ b/spec/features/event_emails_spec.rb
@@ -52,12 +52,12 @@
 
     page.check('Submitted')
     page.check('Incomplete')
-    page.should have_field('To', with: 'gial.ackbar@rebel-alliance.org,luke.skywalker@rebel-alliance.org,evram.lajaie@rebel-alliance.org,'\
-        'c3po@droids.com,wedge.antilles@rebel-alliance.org')
+    mails = 'c3po@droids.com,evram.lajaie@rebel-alliance.org,gial.ackbar@rebel-alliance.org,' \
+      'luke.skywalker@rebel-alliance.org,wedge.antilles@rebel-alliance.org'
+    page.should have_field('To', with: mails)
 
     page.check('All')
-    page.should have_field('To', with: 'gial.ackbar@rebel-alliance.org,luke.skywalker@rebel-alliance.org,evram.lajaie@rebel-alliance.org,'\
-        'c3po@droids.com,wedge.antilles@rebel-alliance.org')
+    page.should have_field('To', with: mails)
 
     fill_in 'Subject', with: "Death Star's destruction celebration"
     fill_in 'event_email_body', with: "Event Death Star's destruction celebration to be conducted soon. Be ready."
diff --git a/spec/helpers/events_helper_spec.rb b/spec/helpers/events_helper_spec.rb
index 2d97861f..0f97b62d 100644
--- a/spec/helpers/events_helper_spec.rb
+++ b/spec/helpers/events_helper_spec.rb
@@ -10,15 +10,19 @@
 
   describe '#users_for_event' do
     it 'returns email of all the participants of the event' do
-      expect(users_for_event('all')).to eq(['gial.ackbar@rebel-alliance.org', 'luke.skywalker@rebel-alliance.org', 'wedge.antilles@rebel-alliance.org',
-                                            'evram.lajaie@rebel-alliance.org', 'c3po@droids.com'])
+      expect(users_for_event('all')).to eq(
+        ['c3po@droids.com', 'evram.lajaie@rebel-alliance.org', 'gial.ackbar@rebel-alliance.org',
+         'luke.skywalker@rebel-alliance.org', 'wedge.antilles@rebel-alliance.org']
+      )
     end
     it 'returns emails of participants with their request in submitted state' do
       expect(users_for_event('submitted')).to eq(['wedge.antilles@rebel-alliance.org'])
     end
     it 'returns emails of participants with their request in incomplete state' do
-      expect(users_for_event('incomplete')).to eq(['gial.ackbar@rebel-alliance.org', 'luke.skywalker@rebel-alliance.org', 'evram.lajaie@rebel-alliance.org',
-                                                   'c3po@droids.com'])
+      expect(users_for_event('incomplete')).to eq(
+        ['c3po@droids.com', 'evram.lajaie@rebel-alliance.org',
+         'gial.ackbar@rebel-alliance.org', 'luke.skywalker@rebel-alliance.org']
+      )
     end
     it 'returns emails of participants with their request in canceled state' do
       expect(users_for_event('canceled')) .to eq([])
diff --git a/spec/models/event_organizer_spec.rb b/spec/models/event_organizer_spec.rb
index 3043993a..f301f787 100644
--- a/spec/models/event_organizer_spec.rb
+++ b/spec/models/event_organizer_spec.rb
@@ -13,6 +13,6 @@
 
   it 'nickname and email of the user' do
     expect(EventOrganizer.autocomplete_users('john')).to eq [['johnsnow', 'john.skywalker@rebel-alliance.org']]
-    expect(EventOrganizer.autocomplete_users('co')).to eq [['C3PO', 'c3po@droids.com'], ['DD-19.A1', 'dd-19.a1@droids.com'], ['commanderlajaier', 'evram.lajaie@rebel-alliance.org']]
+    expect(EventOrganizer.autocomplete_users('co')).to eq [['C3PO', 'c3po@droids.com'], ['commanderlajaier', 'evram.lajaie@rebel-alliance.org'], ['DD-19.A1', 'dd-19.a1@droids.com']]
   end
 end