Figment Backend

Updates the config module to use the figment crate internally, which allows us to support default and environment configs.

Cargo.lock

@@ -75,6 +75,7 @@ name = "collective"
 version = "0.1.1"
 dependencies = [
  "clap",
+ "figment",
  "log",
  "pretty_env_logger",
  "serde",
@@ -95,6 +96,19 @@ dependencies = [
  "termcolor",
 ]
 
+[[package]]
+name = "figment"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f273b2f81f067bb5553f562feb98794d6c704f049d333f920d69211965a30448"
+dependencies = [
+ "pear",
+ "serde",
+ "toml",
+ "uncased",
+ "version_check",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.9.1"
@@ -138,6 +152,12 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "inlinable_string"
+version = "0.1.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3094308123a0e9fd59659ce45e22de9f53fc1d2ac6e1feb9fef988e4f76cad77"
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -171,6 +191,29 @@ version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "afb2e1c3ee07430c2cf76151675e583e0f19985fa6efae47d6848a3e2c824f85"
 
+[[package]]
+name = "pear"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09f612cbd0f9dd03f5dd28a191c48e4148c3b027e41207b32eee130373c6c941"
+dependencies = [
+ "inlinable_string",
+ "pear_codegen",
+ "yansi",
+]
+
+[[package]]
+name = "pear_codegen"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "602cf1780ee9bbca663ea75769e05643e16fe87d7c8ac9f4f385a2ed8940a75c"
+dependencies = [
+ "proc-macro2",
+ "proc-macro2-diagnostics",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "pretty_env_logger"
 version = "0.4.0"
@@ -214,6 +257,19 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "proc-macro2-diagnostics"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bf29726d67464d49fa6224a1d07936a8c08bb3fba727c7493f6cf1616fdaada"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+ "yansi",
+]
+
 [[package]]
 name = "quick-error"
 version = "1.2.3"
@@ -326,6 +382,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "uncased"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "369fa7fd7969c5373541d3c9a40dc1b76ce676fc87aba30d87c0ad3b97fad179"
+dependencies = [
+ "version_check",
+]
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.7.1"
@@ -386,3 +451,9 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "yansi"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fc79f4a1e39857fc00c3f662cbf2651c771f00e9c15fe2abc341806bd46bd71"