Update patterns.md

I instruct them to create a new rospackage and to copy the nodes from the repository.

Author: ErickKramer

content/ros/patterns.md

@@ -8,33 +8,39 @@ This is an introduction practice for service and client
 	```
 	$ git pull origin master
 	```
-2. Create a folder called srv. Inside the folder create a file called "two_ints.srv".
+2. Create a ros_package
+	```
+	$ catkin_create_pkg service_demo std_msgs rospy
+	```
+3. Copy the nodes from the nodes from foundations_course/exercises/ros/services/src/ into the src folder of the package created
+
+4. Create a folder called srv. Inside the folder create a file called "two_ints.srv".
 	```
 	$ mkdir srv
 	$ nano srv/two_int.srv
 	```
-3. In the service file create two int64 variables for the request and a int64 variable for the response
+5. In the service file create two int64 variables for the request and a int64 variable for the response
 
-4. Modify CMakeLists.txt file
+6. Modify CMakeLists.txt file
   ```
   4.1 Inside find_package{catkin REQUIRED COMPONENTS} add message_generation,
 	4.2 Uncomment add_service_files(Files ) and add the name of the service file <two_ints.srv>. PS: < > not required.
 	4.3 Uncomment generate_messages(DEPENDENCIES std_msgs).
   ```
-5. Modify package.xml file
+7. Modify package.xml file
 	```
 	5.1 Uncomment the line <build_depend>message_generation</build_depend>.
 	5.2 Uncommet the line <exec_depend>message_runtime</exec_depend>
 	NOTE: To uncomment delete the <!-- -->.
 	```
-6. Complete the nodes inside src/ by following the instructions.
+8. Complete the nodes inside src/ by following the instructions.
   ```
   Do not forget to make the nodes executable
   $ chmod +x server_demo.py
   $ chmod +x client_demo.py
   ```
 
-7. Build the workspace
+9. Build the workspace
   ```
   $ catkin build
   Alternatively