Move cassandra to it's own category, add descriptions for couchdb & m…

…ongodb while we're at it

catalog/Data_Persistence/SQL_Database_Adapters.yml

@@ -1,8 +1,6 @@
 name: SQL Database Adapters
 description: Low-level adapters for interfacing with various SQL database servers
 projects:
-  - cassandra
-  - cassandra-driver
   - ibm_db
   - jdbc-mysql
   - jdbc-postgres

catalog/Data_Persistence/cassandra_clients.yml

@@ -0,0 +1,11 @@
+name: Cassandra Clients
+description: Apache Cassandra is a distributed open source NoSQL database. These libraries allow you to interface with it.
+projects:
+  - cassandra
+  - cassandra-cql
+  - cassandra-driver
+  - cassandra-orm
+  - cassandra-schema
+  - cassandra-utils
+  - cassandra_record
+  - cassie-rails

catalog/Data_Persistence/couchdb_clients.yml

@@ -1,5 +1,7 @@
 name: CouchDB Clients
-description:
+description: |
+  Apache CouchDB is an open source NoSQL JSON document storage database with an HTTP API. These libraries enable you to interface
+  with it from Ruby.
 projects:
   - couch_potato
   - couchdb

catalog/Data_Persistence/mongodb_clients.yml

@@ -1,5 +1,5 @@
 name: MongoDB Clients
-description: 
+description: MongoDB is a source-available NoSQL document database. These libraries allow you to interface with it.
 projects:
   - mince
   - mongo