fix: dependency libraries

Signed-off-by: Preetham Kamidi <kamidipreetham@gmail.com>

Dockerfile

@@ -1,12 +1,12 @@
-FROM python:3.8.5-slim-buster
+FROM python:3.7-slim-buster
 LABEL author "Preetham Kamidi <kamidipreetham@gmail.com>"
 ENV LC_ALL=C.UTF-8
 ENV LANG=C.UTF-8
 ENV VERIFYTWEET_RUN_FOR_WEB=true
 RUN apt-get update &&  \
     apt-get install -y git build-essential \
     libblas-dev liblapack-dev libatlas-base-dev gfortran  \
-    imagemagick tesseract-ocr libtesseract-dev
+    imagemagick tesseract-ocr libtesseract-dev libffi-dev
 WORKDIR /app
 COPY . .
 RUN pip install -r requirements.txt