added book.toml file

Author: damilolaedwards

book.toml

@@ -0,0 +1,18 @@
+[book]
+authors = ["Trail of Bits"]
+language = "en"
+multilingual = false
+src = "."
+title = "Building Secure Contracts"
+description = "Follow our guidelines and best practices to write secure smart contracts."
+
+[output.html]
+git-repository-url = "https://github.com/crytic/building-secure-contracts"
+edit-url-template = "https://github.com/crytic/building-secure-contracts/edit/master/{path}"
+default-theme = "ayu"
+cname = "crytic.github.io/building-secure-contracts"
+no-section-label = true
+
+[output.html.fold]
+enable = true
+level = 1