feat(config): Change .cobalt.yml to _cobalt.yml

Why?
- Better aligns with other `_` prefixed files in cobalt
- The file is meant for humans
- This is what Jekyll does

Fixes cobalt-org#348

src/bin/cobalt/args.rs

@@ -13,7 +13,7 @@ pub fn get_config_args() -> Vec<clap::Arg<'static, 'static>> {
          .short("c")
          .long("config")
          .value_name("FILE")
-         .help("Config file to use [default: .cobalt.yml]")
+         .help("Config file to use [default: _cobalt.yml]")
          .takes_value(true),
      clap::Arg::with_name("destination")
          .short("d")

src/bin/cobalt/migrate.rs

@@ -1,5 +1,6 @@
 use std::env;
 use std::ffi;
+use std::fs;
 use std::path;
 
 use clap;
@@ -49,6 +50,12 @@ fn migrate_config(config_path: Option<&str>) -> Result<()> {
     };
     let config: cobalt::ConfigBuilder = config.into();
     let content = config.to_string();
+
+    fs::remove_file(&config_path)?;
+
+    let mut config_path = config_path;
+    config_path.set_file_name("_cobalt.yml");
+    let config_path = config_path;
     cobalt_model::files::write_document_file(content, config_path)?;
 
     Ok(())

src/cobalt_model/config.rs

@@ -226,14 +226,14 @@ impl ConfigBuilder {
     }
 
     fn from_cwd_internal(cwd: path::PathBuf) -> Result<ConfigBuilder> {
-        let file_path = files::find_project_file(&cwd, ".cobalt.yml");
+        let file_path = files::find_project_file(&cwd, "_cobalt.yml");
         let config = file_path
             .map(|p| {
                      info!("Using config file {:?}", &p);
                      Self::from_file(&p).chain_err(|| format!("Error reading config file {:?}", p))
                  })
             .unwrap_or_else(|| {
-                warn!("No .cobalt.yml file found in current directory, using default config.");
+                warn!("No _cobalt.yml file found in current directory, using default config.");
                 let config = ConfigBuilder {
                     root: cwd,
                     ..Default::default()
@@ -383,7 +383,7 @@ impl Default for Config {
 
 #[test]
 fn test_from_file_ok() {
-    let result = ConfigBuilder::from_file("tests/fixtures/config/.cobalt.yml").unwrap();
+    let result = ConfigBuilder::from_file("tests/fixtures/config/_cobalt.yml").unwrap();
     assert_eq!(result.root,
                path::Path::new("tests/fixtures/config").to_path_buf());
 }
@@ -435,7 +435,7 @@ fn test_build_default() {
 
 #[test]
 fn test_build_dest() {
-    let result = ConfigBuilder::from_file("tests/fixtures/config/.cobalt.yml").unwrap();
+    let result = ConfigBuilder::from_file("tests/fixtures/config/_cobalt.yml").unwrap();
     let result = result.build().unwrap();
     assert_eq!(result.source,
                path::Path::new("tests/fixtures/config").to_path_buf());
@@ -445,7 +445,7 @@ fn test_build_dest() {
 
 #[test]
 fn test_build_abs_dest() {
-    let mut result = ConfigBuilder::from_file("tests/fixtures/config/.cobalt.yml").unwrap();
+    let mut result = ConfigBuilder::from_file("tests/fixtures/config/_cobalt.yml").unwrap();
     result.abs_dest = Some("hello/world".to_owned());
     let result = result.build().unwrap();
     assert_eq!(result.source,

src/cobalt_model/files.rs

@@ -515,22 +515,22 @@ mod tests {
 
     #[test]
     fn find_project_file_same_dir() {
-        let actual = find_project_file("tests/fixtures/config", ".cobalt.yml").unwrap();
-        let expected = path::Path::new("tests/fixtures/config/.cobalt.yml");
+        let actual = find_project_file("tests/fixtures/config", "_cobalt.yml").unwrap();
+        let expected = path::Path::new("tests/fixtures/config/_cobalt.yml");
         assert_eq!(actual, expected);
     }
 
     #[test]
     fn find_project_file_parent_dir() {
-        let actual = find_project_file("tests/fixtures/config/child", ".cobalt.yml").unwrap();
-        let expected = path::Path::new("tests/fixtures/config/.cobalt.yml");
+        let actual = find_project_file("tests/fixtures/config/child", "_cobalt.yml").unwrap();
+        let expected = path::Path::new("tests/fixtures/config/_cobalt.yml");
         assert_eq!(actual, expected);
     }
 
     #[test]
     fn find_project_file_doesnt_exist() {
         let expected = path::Path::new("<NOT FOUND>");
-        let actual = find_project_file("tests/fixtures/", ".cobalt.yml")
+        let actual = find_project_file("tests/fixtures/", "_cobalt.yml")
             .unwrap_or_else(|| expected.into());
         assert_eq!(actual, expected);
     }

src/new.rs

@@ -61,7 +61,7 @@ pub fn create_new_project<P: AsRef<path::Path>>(dest: P) -> Result<()> {
 pub fn create_new_project_for_path(dest: &path::Path) -> Result<()> {
     fs::create_dir_all(dest)?;
 
-    create_file(&dest.join(".cobalt.yml"), COBALT_YML)?;
+    create_file(&dest.join("_cobalt.yml"), COBALT_YML)?;
     create_file(&dest.join("index.md"), INDEX_MD)?;
 
     fs::create_dir_all(&dest.join("_layouts"))?;