docs(all): update to main replica (#477)

docs/getting-started/examples.md

@@ -42,13 +42,13 @@ with Diagram("Clustered Web Services", show=False):
                      ECS("web3")]
 
     with Cluster("DB Cluster"):
-        db_master = RDS("userdb")
+        db_main = RDS("userdb")
-        db_master - [RDS("userdb ro")]
+        db_main - [RDS("userdb ro")]
 
     memcached = ElastiCache("memcached")
 
     dns >> lb >> svc_group
-    svc_group >> db_master
+    svc_group >> db_main
     svc_group >> memcached
 ```
 
@@ -196,14 +196,14 @@ with Diagram("Advanced Web Service with On-Premise", show=False):
             Server("grpc3")]
 
     with Cluster("Sessions HA"):
-        master = Redis("session")
+        main = Redis("session")
-        master - Redis("replica") << metrics
+        main - Redis("replica") << metrics
-        grpcsvc >> master
+        grpcsvc >> main
 
     with Cluster("Database HA"):
-        master = PostgreSQL("users")
+        main = PostgreSQL("users")
-        master - PostgreSQL("slave") << metrics
+        main - PostgreSQL("replica") << metrics
-        grpcsvc >> master
+        grpcsvc >> main
 
     aggregator = Fluentd("logging")
     aggregator >> Kafka("stream") >> Spark("analytics")
@@ -239,14 +239,14 @@ with Diagram(name="Advanced Web Service with On-Premise (colored)", show=False):
             Server("grpc3")]
 
     with Cluster("Sessions HA"):
-        master = Redis("session")
+        main = Redis("session")
-        master - Edge(color="brown", style="dashed") - Redis("replica") << Edge(label="collect") << metrics
+        main - Edge(color="brown", style="dashed") - Redis("replica") << Edge(label="collect") << metrics
-        grpcsvc >> Edge(color="brown") >> master
+        grpcsvc >> Edge(color="brown") >> main
 
     with Cluster("Database HA"):
-        master = PostgreSQL("users")
+        main = PostgreSQL("users")
-        master - Edge(color="brown", style="dotted") - PostgreSQL("slave") << Edge(label="collect") << metrics
+        main - Edge(color="brown", style="dotted") - PostgreSQL("replica") << Edge(label="collect") << metrics
-        grpcsvc >> Edge(color="black") >> master
+        grpcsvc >> Edge(color="black") >> main
 
     aggregator = Fluentd("logging")
     aggregator >> Edge(label="parse") >> Kafka("stream") >> Edge(color="black", style="bold") >> Spark("analytics")

docs/guides/cluster.md

@@ -22,11 +22,11 @@ with Diagram("Simple Web Service with DB Cluster", show=False):
     web = ECS("service")
 
     with Cluster("DB Cluster"):
-        db_master = RDS("master")
+        db_main = RDS("main")
-        db_master - [RDS("slave1"),
+        db_main - [RDS("replica1"),
-                     RDS("slave2")]
+                     RDS("replica2")]
 
-    dns >> web >> db_master
+    dns >> web >> db_main
 ```
 
 ![simple web service with db cluster diagram](/img/simple_web_service_with_db_cluster_diagram.png)

docs/guides/edge.md

@@ -35,22 +35,22 @@ with Diagram(name="Advanced Web Service with On-Premise (colored)", show=False):
             Server("grpc3")]
 
     with Cluster("Sessions HA"):
-        master = Redis("session")
+        main = Redis("session")
-        master \
+        main \
             - Edge(color="brown", style="dashed") \
             - Redis("replica") \
             << Edge(label="collect") \
             << metrics
-        grpcsvc >> Edge(color="brown") >> master
+        grpcsvc >> Edge(color="brown") >> main
 
     with Cluster("Database HA"):
-        master = PostgreSQL("users")
+        main = PostgreSQL("users")
-        master \
+        main \
             - Edge(color="brown", style="dotted") \
-            - PostgreSQL("slave") \
+            - PostgreSQL("replica") \
             << Edge(label="collect") \
             << metrics
-        grpcsvc >> Edge(color="black") >> master
+        grpcsvc >> Edge(color="black") >> main
 
     aggregator = Fluentd("logging")
     aggregator \