diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..21c9e0c
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "external/curl"]
+	path = external/curl
+	url = https://github.com/curl/curl
+[submodule "external/jsoncpp"]
+	path = external/jsoncpp
+	url = https://github.com/open-source-parsers/jsoncpp
diff --git a/docs/class-diagram.png b/docs/class-diagram.png
index 01a44b9..6aa233d 100644
Binary files a/docs/class-diagram.png and b/docs/class-diagram.png differ
diff --git a/docs/dev.org b/docs/dev.org
index 99d18c8..dd74995 100644
--- a/docs/dev.org
+++ b/docs/dev.org
@@ -8,12 +8,15 @@
 #+BEGIN_SRC plantuml :file class-diagram.png :exports result
 @startuml
 Exchange <|--- Binance
-Market <--- "-currencies" Currency : 2
-Exchange *--- " #markets" Market : 1..*
-Trader <--- "-exchanges" Exchange: 1..*
-TradeTracker *--- "-traders" Trader: 0..*
+Market <--- "-currencies 2" Currency
+Exchange *--- " #markets 1..*" Market 
+Trader <--- " #exchanges 1..*" Exchange
+TradeTracker *--- "-exchanges 1...*" Exchange
+TradeTracker *--- "-traders 0..*" Trader
+Market <... TradeTracker 
+Market <... Trader
 
-class TradeTracker {
+class TradeTracker << (S,#FF7700) Singleton >> {
    -round()
    +start()
 }
@@ -22,7 +25,7 @@ abstract class Trader {
    +{abstract} step()
 }
 
-note right of Trader::step()
+note left of Trader::step()
   Itt történik a trader belső logikája
 end note
 
@@ -44,7 +47,7 @@ class Binance {
   +updateMarkets()
 }
 
-note left of Binance
+note right of Binance
   Ez csak egy példa, lehetne akár más is
 end note
 
diff --git a/docs/my-diagram.png b/docs/my-diagram.png
new file mode 100644
index 0000000..d93cab8
Binary files /dev/null and b/docs/my-diagram.png differ
diff --git a/external/curl b/external/curl
index aa8de5d..5a19cb5 160000
--- a/external/curl
+++ b/external/curl
@@ -1 +1 @@
-Subproject commit aa8de5d6ee457456ce665282d1bf5d74648683dc
+Subproject commit 5a19cb5a3c1b0345306bb3738a0cdf43ea72852b
diff --git a/external/jsoncpp b/external/jsoncpp
index 9409824..c9a9762 160000
--- a/external/jsoncpp
+++ b/external/jsoncpp
@@ -1 +1 @@
-Subproject commit 940982438d01fe2575acef8dd98a9b6893ccc9bb
+Subproject commit c9a976238b8b184a5a2e3b6bfa513ba1657a327b