Update Readme, add solder instructions

solder_instructions.md

@@ -38,17 +38,9 @@ What is...
 
 
 
-<div class="panel panel-danger">
-
-**Gotchas**
-{: .panel-heading}
-
-<div class="panel-body">
 
 ⚠️  The silkscreen of the RGB-LED is on the <u>wrong</u> side of the PCB! Solder it on the other side.
-
-</div>
-</div>
+{: .alert .alert-info}
 
 ## Before soldering