diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..e0e6c86
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,4 @@
+language: cpp
+os: linux
+script:
+  - make
diff --git a/Inventory.cpp b/Inventory.cpp
index de8e7b8..9a4b2fc 100644
--- a/Inventory.cpp
+++ b/Inventory.cpp
@@ -4,7 +4,12 @@
 
 using std::string;
 using std::ostream;
-  
+using std::cout;
+
+// Constructor
+// @param string name - The name of the item to add
+// @param float price - The price of the item to add
+// @param int count   - The quantity of the item to add  
 Inventory::Inventory(string name, float price, int count)
 {
   m_name = name;
@@ -12,14 +17,21 @@ Inventory::Inventory(string name, float price, int count)
   m_in_stock = count;
 }
 
+// Decrements stock of item, unless quantity is 0
 void Inventory::sell()
 {
-  m_in_stock--;
+	if (m_in_stock == 0){
+		cout << "Sorry, that item is out of stock.\n";
+  }
+	else {
+	  m_in_stock--;
+	}
 }
 
+// Prints information about the item
 ostream& operator<<(ostream& stream, const Inventory& item)
 {
   stream << item.m_name << " $"
          << std::fixed << std::setprecision(2) << item.m_price;
   return stream;
-}
\ No newline at end of file
+}
diff --git a/Inventory.h b/Inventory.h
index c52d5d8..4d465d0 100644
--- a/Inventory.h
+++ b/Inventory.h
@@ -5,11 +5,15 @@
 using std::string;
 using std::ostream;
 
+// This class is used to keep track of an item in the shop's inventory.
 class Inventory
 {
   private:
+		// Name of the item
     string m_name;
+		// Price of the item
     float m_price;
+		// Quantity of item left in stock
     int m_in_stock;
 
   public:
@@ -18,4 +22,4 @@ class Inventory
     friend ostream& operator<<(ostream&, const Inventory&);
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..675cf53
--- /dev/null
+++ b/README.md
@@ -0,0 +1,5 @@
+[![Build Status](https://travis-ci.org/Dragongoat/Inventory.svg?branch=master)](https://travis-ci.org/Dragongoat/Inventory)
+
+This application simulates a shop, where items can be added to the shop's stock and sold.
+
+To build, simply type "make" in the command line, then run the executable.