fix link typo (#299)

beginner/chapters/webapps.md

@@ -258,7 +258,7 @@ Create a directory called `templates` and create an **index.html** file in that
 </html>
 ```
 ### 2.3.2 Write a Dockerfile
-We want to create a Docker image with this web app. As mentioned above, all user images are based on a _base image_. Since our application is written in Python, we will build our own Python image based on [Alpine](https://store.docker.com/images/alpine. We'll do that using a **Dockerfile**.
+We want to create a Docker image with this web app. As mentioned above, all user images are based on a _base image_. Since our application is written in Python, we will build our own Python image based on [Alpine](https://store.docker.com/images/alpine). We'll do that using a **Dockerfile**.
 
 A [Dockerfile](https://docs.docker.com/engine/reference/builder/) is a text file that contains a list of commands that the Docker daemon calls while creating an image. The Dockerfile contains all the information that Docker needs to know to run the app &#8212; a base Docker image to run from, location of your project code, any dependencies it has, and what commands to run at start-up. It is a simple way to automate the image creation process. The best part is that the [commands](https://docs.docker.com/engine/reference/builder/) you write in a Dockerfile are *almost* identical to their equivalent Linux commands. This means you don't really have to learn new syntax to create your own Dockerfiles.