diff --git a/bootstrap.php b/bootstrap.php
index ba554f7..2abef32 100644
--- a/bootstrap.php
+++ b/bootstrap.php
@@ -2,3 +2,5 @@
 
 require "autoloader.php";
 require "error_handler.php";
+require "config/config.php";
+require "dic.php";
diff --git a/config-dev/config.dev.php b/config-dev/config.dev.php
new file mode 100644
index 0000000..b212138
--- /dev/null
+++ b/config-dev/config.dev.php
@@ -0,0 +1,6 @@
+<?php
+
+function getDatabase()
+{
+    return new PDO("mysql:host=localhost;dbname=sample", "sampleuser", "samplepass", [PDO::ATTR_PERSISTENT => true]);
+}
diff --git a/config-dev/config.php b/config-dev/config.php
new file mode 120000
index 0000000..72705bf
--- /dev/null
+++ b/config-dev/config.php
@@ -0,0 +1 @@
+config.dev.php
\ No newline at end of file
diff --git a/config-dev/db-connection.php b/config-dev/db-connection.php
deleted file mode 100644
index 0ce1428..0000000
--- a/config-dev/db-connection.php
+++ /dev/null
@@ -1,3 +0,0 @@
-<?php
-
-return new PDO("mysql:host=localhost;dbname=sample", "sampleuser", "samplepass", [PDO::ATTR_PERSISTENT => true]);
diff --git a/dic.php b/dic.php
new file mode 100644
index 0000000..962a50b
--- /dev/null
+++ b/dic.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * Returns the best negotiated format according to RFC 7231.
+ */
+function getNegotiatedFormat()
+{
+    return (new \Negotiation\Negotiator())
+        ->getBest($_SERVER["HTTP_ACCEPT"], ['text/html', 'application/json'])
+        ->getValue();
+}
+
+function getTweetsService()
+{
+    return new Service\TweetsService(
+        getDatabase()
+    );
+}
+
+function getUsersService()
+{
+    return new Service\UsersService(
+        getDatabase()
+    );
+}
diff --git a/dic/negotiated_format.php b/dic/negotiated_format.php
deleted file mode 100644
index fd1162f..0000000
--- a/dic/negotiated_format.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-/**
- * Returns the best negotiated format according to RFC 7231.
- */
-
-return (new \Negotiation\Negotiator())
-    ->getBest($_SERVER["HTTP_ACCEPT"], ['text/html', 'application/json'])
-    ->getValue();
diff --git a/dic/tweets.php b/dic/tweets.php
deleted file mode 100644
index dbe8c1e..0000000
--- a/dic/tweets.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-return new Service\TweetsService(
-    require "config/db-connection.php"
-);
diff --git a/dic/users.php b/dic/users.php
deleted file mode 100644
index 9a958c4..0000000
--- a/dic/users.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-return new Service\UsersService(
-    require "config/db-connection.php"
-);
diff --git a/web/index.php b/web/index.php
index ec8e4c1..d515253 100644
--- a/web/index.php
+++ b/web/index.php
@@ -1,8 +1,8 @@
 <?php
 
-$lastJoinedUsers = (require "dic/users.php")->getLastJoined();
+$lastJoinedUsers = getUsersService()->getLastJoined();
 
-switch (require "dic/negotiated_format.php") {
+switch (getNegotiatedFormat()) {
     case "text/html":
         (new Views\Layout(
             "Twitter - Newcomers", new Views\Users\Listing($lastJoinedUsers), true
diff --git a/web/tweet.php b/web/tweet.php
index a3a5c56..6cfe3b0 100644
--- a/web/tweet.php
+++ b/web/tweet.php
@@ -1,6 +1,6 @@
 <?php
 
-$tweet = (require "dic/tweets.php")->getById($_GET["id"]);
+$tweet = getTweetsService()->getById($_GET["id"]);
 
 if ($tweet === null) {
     http_response_code(404);
@@ -14,12 +14,12 @@
     exit;
 }
 
-switch (require "dic/negotiated_format.php") {
+switch (getNegotiatedFormat()) {
     case "text/html":
         (new Views\Layout(
             "@$_GET[user] - \"$tweet->message\"",
             new Views\Tweets\Page(
-                (require "dic/users.php")->getById($_GET["user"]),
+                getUsersService()->getById($_GET["user"]),
                 $tweet
             )
         ))();
diff --git a/web/user.php b/web/user.php
index f88a31c..760a06c 100644
--- a/web/user.php
+++ b/web/user.php
@@ -1,18 +1,18 @@
 <?php
 
-$user = (require "dic/users.php")->getById($_GET["id"]);
+$user = getUsersService()->getById($_GET["id"]);
 
 if ($user === null) {
     http_response_code(404);
     return;
 }
 
-$tweetsService = (require "dic/tweets.php");
+$tweetsService = getTweetsService();
 
 $tweets = $tweetsService->getLastByUser($_GET["id"]);
 $tweetsCount = $tweetsService->getTweetsCount($_GET["id"]);
 
-switch (require "dic/negotiated_format.php") {
+switch (getNegotiatedFormat()) {
     case "text/html":
         (new Views\Layout(
             "Tweets from @$_GET[id]",