Add initial (#1)

src/config.rs

@@ -0,0 +1,40 @@
+extern crate toml;
+use serde_derive::Deserialize;
+use std::fs;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parse_config() {
+        let file = "./examples/config.toml";
+        parse(&file);
+    }
+}
+
+#[derive(Deserialize, Debug)]
+pub struct Config {
+    pub expressions: Vec<String>,
+    pub sendgrid: Sendgrid,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct Sendgrid {
+    pub mail_from: String,
+    pub mail_to: String,
+    pub api_key: String,
+}
+
+pub fn parse(filename: &str) -> Config {
+    let contents = fs::read_to_string(filename)
+        .unwrap_or_else(|e| panic!("Unable to read configuration file '{}'. {}", filename, e));
+    let config: Config = toml::from_str(&contents).unwrap_or_else(|e| {
+        panic!(
+            "Unable to parse configuration with contents: {}. {}",
+            contents, e
+        )
+    });
+
+    config
+}