Migrate to Swift 4.0.2 (#70)

.gitignore

@@ -1,5 +1,5 @@
 .build/
 build
-Packages/
+Package.resolved
 Kitura-CouchDB.xcodeproj
 *.DS_Store

.swift-version

@@ -1 +1 @@
-3.1.1
+4.0.2

.travis.yml

@@ -14,17 +14,9 @@ matrix:
     - os: linux
       dist: trusty
       sudo: required
-    - os: linux
-      dist: trusty
-      sudo: required
-      env: SWIFT_SNAPSHOT=$SWIFT_4_DEV_SNAPSHOT
-    - os: osx
-      osx_image: xcode8.3
-      sudo: required
     - os: osx
-      osx_image: xcode9
+      osx_image: xcode9.1
       sudo: required
-      env: SWIFT_SNAPSHOT=$SWIFT_4_DEV_SNAPSHOT
 
 before_install:
   - git clone https://github.com/IBM-Swift/Package-Builder.git

Package.swift

@@ -1,3 +1,6 @@
+// swift-tools-version:4.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
 /**
  * Copyright IBM Corporation 2016, 2017
  *
@@ -18,19 +21,30 @@ import PackageDescription
 
 let package = Package(
     name: "Kitura-CouchDB",
+    products: [
+        // Products define the executables and libraries produced by a package, and make them visible to other packages.
+        .library(
+            name: "CouchDB",
+            targets: ["CouchDB"]),
+        ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+        .package(url: "https://github.com/IBM-Swift/HeliumLogger.git", .upToNextMinor(from: "1.7.0")),
+        .package(url: "https://github.com/IBM-Swift/Kitura-net.git", .upToNextMinor(from: "2.0.0")),
+        .package(url: "https://github.com/IBM-Swift/SwiftyJSON.git", .upToNextMinor(from: "17.0.0")),
+    ],
     targets: [
-        Target(
+        // Targets are the basic building blocks of a package. A target defines a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
+        .target(
             name: "CouchDB",
-            dependencies: []
-        ),
-        Target(
+            dependencies: ["HeliumLogger", "KituraNet", "SwiftyJSON"]),
+        .target(
             name: "CouchDBSample",
-            dependencies: [.Target(name: "CouchDB")]
-        ),
-    ],
-    dependencies: [
-        .Package(url: "https://github.com/IBM-Swift/HeliumLogger.git", majorVersion: 1, minor: 7),
-        .Package(url: "https://github.com/IBM-Swift/Kitura-net.git", majorVersion: 1, minor: 7),
-        .Package(url: "https://github.com/IBM-Swift/SwiftyJSON.git", majorVersion: 17)
-    ]
+            dependencies: ["CouchDB"]),
+        .testTarget(
+            name: "CouchDBTests",
+            dependencies: ["CouchDB"]),
+        ]
 )

Sources/CouchDB/Database.swift

@@ -433,8 +433,8 @@ public class Database {
             }
         }
 
-        if paramString.characters.count > 0 {
-            paramString = "?" + String(paramString.characters.dropLast())
+        if paramString.count > 0 {
+            paramString = "?" + String(paramString.dropLast())
         }
 
         var method = "GET"