refactor: use heroku.yml and run migrations in release phase

heroku.Dockerfile

@@ -0,0 +1,20 @@
+FROM python:3.9
+
+# Install dependencies
+RUN apt-get update
+RUN apt-get install curl libpq-dev postgresql-client nodejs yarnpkg -y
+
+# Set working directory
+WORKDIR /home/indexer
+
+# Copy source code
+COPY . .
+
+# Install indexer and pin the version of poetry
+RUN pip3 install poetry==1.6.1
+RUN poetry install
+# the heroku.yml 'run' directive is incompatible with poetry
+# so we export to the requirements.txt format and use pip3 
+RUN poetry export --without-hashes --format=requirements.txt > requirements.txt
+RUN pip3 install -r requirements.txt 
+RUN yarnpkg install

heroku.yml

@@ -0,0 +1,9 @@
+build:
+  docker:
+    indexer: heroku.Dockerfile
+run:
+  indexer: python main.py
+release:
+  image: indexer
+  command:
+    - PGSSLMODE=no-verify yarnpkg migrate