ISSUE-90 add 4 rules for CMD and ENTRYPOINT

dockerfiles/README.md

@@ -59,6 +59,14 @@ Options:
   -c filename   : set configuration file (default: /etc/nginx/nginx.conf)
   -g directives : set global directives out of configuration file
 ```
+### 4 Rules
+There's 4 rules that describe how CMD and `ENTRYPOINT` interact.
+
+![](/docs/images/entrypoint-cmd-4rules.png)
+
+Here's another way to visualize what command is executed for different ENTRYPOINT / CMD combinations.
+
+![](/docs/images/entrypoint-cmd-interaction.png)
 
 #### Summary
 
@@ -75,22 +83,21 @@ You might be wondering if Docker provides a way to modify the `ENTRYPOINT`  with
 
 The `docker run` command has an optional `--entrpoint` flag for this.
 
-![](/docs/images/--entrypoint.png)
+![](/docs/images/entrypoint-flag.png)
 
 Let's see an example that modifies both default entrypoint and command. In the previous lecture we saw how we could print nginx help text by creating a custom image. You can do the same thing in the command line.
 
 Run:
 
 ```
 docker run --rm --entrypoint nginx nginx:1.21.4 -h
-````
+```
 
 In summary, you're not forced to create a new image to make changes to the entrypoint. Using the `--entrypoint` flag gives you an alternative approach while using `docker run` and any comamands and aruguments can be appended to the end like usual. 
 
 Resources
 - https://docs.docker.com/engine/reference/commandline/run/#options
 
-
 ### Lecture 3: Using ENTRYPOINT and CMD in Docker Compose
 
 We've seen how we can use entrypoint and command together in our Dockerfiles and with the `docker run` command, but how does it work with `docker-compose`?