Unique emails and added can_receive

Dockerfile.dev

@@ -1,7 +1,12 @@
-FROM python:3.8.1
+FROM python:3.8.12-slim-buster
 
 RUN apt-get -y update && apt-get -y upgrade && \
-    apt-get install --no-install-recommends -y wait-for-it postgresql-client vim
+    apt-get install --no-install-recommends -y wait-for-it lsb-release wget gnupg2 gcc libpq-dev libc-dev vim
+
+# install psql 13 (11 is the default with debian)
+RUN wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
+RUN echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" | tee /etc/apt/sources.list.d/pgdg.list
+RUN apt-get update && apt-get --no-install-recommends -y install postgresql-client-13 && apt-get clean all
 
 WORKDIR /app