requirements: Include stripe in common.in.

requirements/common.in

@@ -185,3 +185,6 @@ lxml==4.1.0
 # Needed for 2-factor authentication
 django-two-factor-auth==1.6.2
 twilio==6.9.0
+
+# Needed for processing payments
+stripe==1.77.0

requirements/dev.txt

@@ -135,7 +135,7 @@ recommonmark==0.4.0
 redis==2.10.6
 regex==2017.11.9
 requests-oauthlib==0.8.0
-requests==2.18.4          # via aws-xray-sdk, docker, moto, premailer, pyoembed, python-digitalocean, python-gcm, python-twitter, requests-oauthlib, social-auth-core, sphinx, twilio
+requests==2.18.4          # via aws-xray-sdk, docker, moto, premailer, pyoembed, python-digitalocean, python-gcm, python-twitter, requests-oauthlib, social-auth-core, sphinx, stripe, twilio
 rsa==3.4.2
 s3transfer==0.1.11        # via boto3
 scrapy==1.4.0
@@ -155,6 +155,7 @@ sphinx==1.6.5
 sphinxcontrib-websupport==1.0.1  # via sphinx
 sqlalchemy==1.1.14
 statsd==3.2.1             # via django-statsd-mozilla
+stripe==1.77.0
 tblib==1.3.2
 tornado==4.5.2
 traitlets==4.3.2          # via ipython

requirements/prod.txt

@@ -97,7 +97,7 @@ qrcode==4.0.4             # via django-two-factor-auth
 redis==2.10.6
 regex==2017.11.9
 requests-oauthlib==0.8.0
-requests==2.18.4          # via premailer, pyoembed, python-gcm, python-twitter, requests-oauthlib, social-auth-core, twilio
+requests==2.18.4          # via premailer, pyoembed, python-gcm, python-twitter, requests-oauthlib, social-auth-core, stripe, twilio
 rsa==3.4.2
 simplegeneric==0.8.1      # via ipython
 six==1.11.0
@@ -108,6 +108,7 @@ sockjs-tornado==1.0.3
 sourcemap==0.2.1
 sqlalchemy==1.1.14
 statsd==3.2.1             # via django-statsd-mozilla
+stripe==1.77.0
 tornado==4.5.2
 traitlets==4.3.2          # via ipython
 twilio==6.9.0