Add in-memory caching

Author: lorensr

app/src/main/java/guide/graphql/toc/Apollo.kt

@@ -1,7 +1,13 @@
 package guide.graphql.toc
 
 import com.apollographql.apollo.ApolloClient
+import com.apollographql.apollo.cache.normalized.lru.EvictionPolicy
+import com.apollographql.apollo.cache.normalized.lru.LruNormalizedCacheFactory
+
+val cacheFactory =
+    LruNormalizedCacheFactory(EvictionPolicy.builder().maxSizeBytes(10 * 1024 * 1024).build())
 
 val apolloClient: ApolloClient = ApolloClient.builder()
     .serverUrl("https://api.graphql.guide/graphql")
+    .normalizedCache(cacheFactory)
     .build()