Add config.toml as a mapped file instead of copying

This should reduce the number of rebuilds that we have to do for a
simple configuration change

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

Dockerfile

@@ -6,5 +6,4 @@ RUN pip3 install pipenv
 RUN apk add build-base libffi-dev
 COPY ./Pipfile ./Pipfile.lock /app/
 RUN pipenv install
-COPY ./config.toml /app/
-CMD pipenv run python3 -m omnibot
+CMD pipenv run python3 -m omnibot

docker-compose.yml

@@ -6,4 +6,5 @@ services:
       - "./omnibot:/app/omnibot"
       - "./plugins:/app/plugins"
       - "./data:/app/data"
+      - "./config.toml:/app/config.toml"
     restart: unless-stopped