add pip requirements

requirements.txt

+bcrypt==3.1.7
+ffmpy==0.2.2
+Flask==1.1.1
+Flask-Caching==1.8.0
+Flask-Session==0.3.1
+Flask-WTF==0.14.3
+gunicorn==20.0.4
+jsonschema==3.2.0
+pymongo==3.10.1
+redis==3.4.1
+requests==2.23.0
+websockets==7.0