chore: add more rules

Author: Dun-sin

CONTRIBUTING.md

@@ -1,8 +1,10 @@
 ### Contributing guidelines
 
 ## Rules 
-- Don't work on anything unless you are assigned, if you make a pull request without being assigned to that issue, it will be closed without being merged 
+- Don't create a pull request on an issue that doesn't exist, create an issue first and if the changes you are proposing are said to be okay, you can go ahead and create a pull request 
+- Don't work on anything unless you are assigned, if you make a pull request without being assigned to that issue, it will be closed without being merged
 - Don't work on more than one issue at a time, this is so that you don't make a huge pull request and others can have opportunities to work on another issue while you work on something else 
+- Do read the `readme.md` file
 
 ## 👩🏽‍💻 Prerequisite Skills to Contribute