Add content in consistency patterns

src/roadmaps/system-design/content/104-consistency-patterns/index.md

@@ -1 +1,13 @@
-# Consistency patterns
+# Consistency Patterns
+
+Consistency patterns refer to the ways in which data is stored and managed in a distributed system, and how that data is made available to users and applications. There are three main types of consistency patterns:
+
+- Strong consistency
+- Weak consistency
+- Eventual Consistency
+
+Each of these patterns has its own advantages and disadvantages, and the choice of which pattern to use will depend on the specific requirements of the application or system.
+
+Have a look at the following resources to learn more:
+
+- [Consistency Patterns in Distributed Systems](https://cs.fyi/guide/consistency-patterns-week-strong-eventual/)