allow for comments in the env file, and fix the readme

Author: zigster64

.env

@@ -0,0 +1,11 @@
+# A comment here
+
+VALUE1=1
+VALUE2=2
+VALUE3=3
+
+# some blank lines
+
+
+
+# VALUE4=4

.gitignore

@@ -1,3 +1,2 @@
 zig-out/
 .zig-cache/
-.env

README.md

@@ -3,6 +3,18 @@ Load ENV vars from .env files on boot
 
 -- 
 
+On boot, calling `env.init(alloc, ".env")` will return an env that 
+includes values from the `.env` file
+
+Lines starting with `#` are treated as comments
+
+All other lines will take the form 
+
+```
+ENV_VAR_NAME=VALUE
+```
+
+Lines that do not have a `=` sign will be skipped
 
 ## Install
 
@@ -13,7 +25,7 @@ zig fetch --save git+https://github.com/zigster64/dotenv.zig#main
 Then add to your build.zig
 
 ```zig
-    const zts = b.dependency("dotenv", .{ dependency options here );
+    const dotenv = b.dependency("dotenv", .{ dependency options here );
     exe.root_module.addImport("dotenv", dotenv.module("dotenv"));
 ```
 
@@ -39,7 +51,7 @@ pub fn main() !void {
     defer gpa.deinit();
 
     // init the dotenv object - this will read the .env file at runtime
-    const env = try dotenv.init(allocator, ".env");
+    var env = try dotenv.init(allocator, ".env");
     defer env.deinit();
 
     // gen "Env" vars

src/dotenv.zig

@@ -19,6 +19,10 @@ pub fn init(allocator: Allocator, filename: ?[]const u8) !Self {
         var in_stream = buf_reader.reader();
         var buf: [1024]u8 = undefined;
         while (try in_stream.readUntilDelimiterOrEof(&buf, '\n')) |line| {
+            // ignore commented out lines
+            if (line.len > 0 and line[0] == '#') {
+                continue;
+            }
             // split into KEY and Value
             if (std.mem.indexOf(u8, line, "=")) |index| {
                 const key = line[0..index];
@@ -57,4 +61,5 @@ test "load an env file" {
     try testing.expectEqualStrings("1", expanded_env.get("VALUE1").?);
     try testing.expectEqualStrings("2", expanded_env.get("VALUE2").?);
     try testing.expectEqualStrings("3", expanded_env.get("VALUE3").?);
+    try testing.expectEqual(null, expanded_env.get("VALUE4"));
 }