Update demo video text editor

When applying Git commits, Vi was previously used. Changing to Vim
allowed for the use of a plugin supporting Git commits which provided
many benefits including adding colour.

The plugin did not hard wrap commit messages to 72 characters and this
option was necessary to add to the custom settings. The previous method
for setting options did not handle multiple options. Using a
configuration file was necessary.

scripts/video/Dockerfile

@@ -10,13 +10,18 @@ RUN apk add --no-cache \
 
 RUN ln -s /usr/share/git-core/git-prompt.sh /etc/profile.d/
 
+ENV EDITOR vim
 ENV GIT_PS1_SHOWDIRTYSTATE 1
 ENV GIT_PS1_SHOWSTASHSTATE 1
 ENV GIT_PS1_SHOWUNTRACKEDFILES 1
 ENV GIT_PS1_SHOWUPSTREAM auto
 ENV GIT_PS1_SHOWCOLORHINTS 1
 ENV PROMPT_COMMAND '__git_ps1 "\w" " \\\$ "'
-ENV VIMINIT "set nofixendofline"
+
+COPY <<EOF /etc/vim/vimrc.local
+set nofixendofline
+set textwidth=72
+EOF
 
 RUN git config --global user.name "John Doe"
 RUN git config --global user.email [email protected]