Add serde feature to petgraph dependency

Cargo.lock

@@ -45,4 +45,58 @@ checksum = "4dd7d28ee937e54fe3080c91faa1c3a46c06de6252988a7f4592ba2310ef22a4"
 dependencies = [
  "fixedbitset",
  "indexmap",
+ "serde",
+ "serde_derive",
 ]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.59"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6aeca18b86b413c660b781aa319e4e2648a3e6f9eadc9b47e9038e6fe9f3451b"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b9ab9c7eadfd8df19006f1cf1a4aed13540ed5cbc047010ece5826e10825488"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "serde"
+version = "1.0.163"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2113ab51b87a539ae008b5c6c02dc020ffa39afd2d83cffcb3f4eb2722cebec2"
+
+[[package]]
+name = "serde_derive"
+version = "1.0.163"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8c805777e3930c8883389c602315a24224bcc738b63905ef87cd1420353ea93e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "syn"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45b6ddbb36c5b969c182aec3c4a0bce7df3fbad4b77114706a49aacc80567388"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15811caf2415fb889178633e7724bad2509101cde276048e013b9def5e51fa0"

Cargo.toml

@@ -11,4 +11,4 @@ categories = [ "science", "simulation"]
 publish = false
 
 [dependencies]
-petgraph = "0.6.3" # the graph library
+petgraph = {version="0.6.3", features = ["serde-1"]} # the graph library
\ No newline at end of file