Extracted redis connection and quota check to be reusable

server/extension/sql/0.0.1/11_redis_helper.sql

@@ -0,0 +1,11 @@
+-- Get the connection to redis from cache or create a new one
+CREATE OR REPLACE FUNCTION cdb_geocoder_server._connect_to_redis(user_id name)
+RETURNS boolean AS $$
+  if user_id in GD and 'redis_connection' in GD[user_id]:
+    return False
+  else:
+    from cartodb_geocoder import redis_helper
+    redis_connection = redis_helper.RedisHelper('localhost', 6379, 5).redis_connection()
+    GD[user_id] = {'redis_connection': redis_connection}
+    return True
+$$ LANGUAGE plpythonu;