Add Grakn (sindresorhus#1938)

Co-authored-by: Sindre Sorhus <[email protected]>

readme.md

@@ -470,6 +470,7 @@
 - [NoSQL Guides](https://github.com/erictleung/awesome-nosql-guides#readme) - Help on using non-relational, distributed, open-source, and horizontally scalable databases.
 - [Contexture](https://github.com/ltchris/awesome-contexture#readme) - Abstracts queries/filters and results/aggregations from different backing data stores like ElasticSearch and MongoDB.
 - [Database Tools](https://github.com/mgramin/awesome-db-tools#readme) - Everything that makes working with databases easier.
+- [Grakn](https://github.com/graknlabs/awesome#readme) - Logical database to organize large and complex networks of data as one body of knowledge.
 
 ## Media