Updated the instruction for the MySQL connector

We encourage to always download the newest connector. 

docs/source/setup.md

@@ -67,8 +67,7 @@ You could skip this section if you don't plan to run the whole Nexus-e platform
 
   - Set up database connector
 
-    - Download the **MySQL connector** from [here](https://dev.mysql.com/downloads/connector/j/).
-    Or, if you have access to the Nexus-e polybox, use the `mysql-connector-java-8.0.18.zip` provided in the folder `02_Model/02_Model_Setup_Instruction` (**Unzip** the file before the next step).
+    - Download the **MySQL connector** from [here](https://dev.mysql.com/downloads/connector/j/). **Unzip** the file.
 
     - Copy the MySQL connector folder (e.g. mysql-connector-java-8.0.18) into a folder at your preference.
     We recommend to put it into the **Matlab preferences folder**, which you can find by typing in Matlab Command Window ```prefdir```.